user11009: 
Modes of Production
“What is it that is kamma-born, what cause-born, and what
season-born? What is it that is none of these?”
“All beings, O king are kamma-born. Fire, and all things
growing out of seeds are cause-born. The earth, water and
wind are season-born. Space and nibbàna exist independently
of kamma, cause and season. Of nibbàna, O king, it cannot
be said that it is perceptible by the five senses, but it is perceptible
by the mind. The disciple whose mind is pure, and
free from obstructions, can perceive nibbàna.

http://www.buddhanet.net/pdf_file/milinda.pdf

user8157: Space does not exist independently of kamma & cause. By kamma (action), space can be filled, such as filling a hole with soil. Or by cause, space can be created or removed, such as a volcanic eruption creating a cave with space but filling space in a crevice. Or when sickness blocks the space in the nostril. 
The Lord Buddha said the realisation of space is conditioned & not Nibbana. 
Nibbana is dispassion; Nibbana is non-attachment; Nibbana is the destruction of craving; Nibbana is the absence of greed, hatred & delusion. Therefore, a mind abiding in Nibbana can walk & talk. Where as a mind abiding in space cannot walk or talk. That is why the Buddha rejected the dimension of the infinitude of space as Nibbana; because the dimension of the infinitude of space is limited, bondage, conditioned & not freedom.  

One discerns that 'If I were to direct equanimity as pure & bright as this towards the dimension of the infinitude of space and to develop
  the mind along those lines, that would be fabricated'. MN 140

And what is the space property?... Anything... that is space, spatial... the holes of the ears, the nostrils, the mouth, the
  [passage] whereby what is eaten, drunk, consumed & tasted gets
  swallowed, and where it collects... MN 62



In the course of the future there will be monks who won't listen when discourses that are words of the Tathagata — deep, deep in their
  meaning, transcendent, connected with emptiness — are being recited.
  They won't lend ear, won't set their hearts on knowing them, won't
  regard these teachings as worth grasping or mastering. But they will
  listen when discourses that are literary works — the works of poets,
  elegant in sound, elegant in rhetoric, the work of outsiders, words of
  disciples — are recited. They will lend ear and set their hearts on
  knowing them. They will regard these teachings as worth grasping &
  mastering. In this way the disappearance of the discourses that are
  words of the Tathagata — deep, deep in their meaning, transcendent,
  connected with emptiness — will come about. SN 20.7


user254: What do you mean by "realize"? See the definition of Ākāsa here, which begins,

'space', is, according to Com., of two kinds: 

limited space (paricchinnākāsa or paricchedākāsa), 
endless space (anantākāsa), i.e. cosmic space.

1) Limited space, under the name of ākāsa-dhātu (space element), belongs to derived corporeality (s. khandha, Summary I; Dhs 638) and to a six fold classification of elements (s. dhātu; M.112, M.115, M.140). It is also an object of kasina meditation. It is defined as follows: "The space element has the characteristic of delimiting matter. Its function is to indicate the boundaries of matter. It is manifested as the confines of matter; or its manifestation consists in being untouched (by the 4 great elements), and in holes and apertures. Its proximate cause is the matter delimited. It is on account of the space element that one can say of material things delimited that 'this is above. below, around that' " (Vis.M. XIV.63).
2) Endless space is called in Atthasālini ajatākāsa, 'unentangled', i.e. unobstructed or empty space. It is the object of the first immaterial absorption (s. jhāna), the sphere of boundless space (ākāsānañcāyatana). According to Abhidhamma philosophy, endless space has no objective reality (being purely conceptual), which is indicated by the fact that it is not included in the triad of the wholesome (kusalatika), which comprises the entire reality. Later Buddhist schools have regarded it as one of several unconditioned or uncreated states (asankhata dharma) - a view that is rejected in Kath. (s. Guide. p. 70). Theravāda Buddhism recognizes only Nibbāna as an unconditioned element (asankhata-dhātu: s. Dhs. 1084).

So maybe people do perceive space: both limited space (in ordinary perception) and unlimited space (as an object of meditation).

11009: <ol start="66">
<li>Modes of Production
“What is it that is kamma-born, what cause-born, and what
season-born? What is it that is none of these?”
“All beings, O king are kamma-born. Fire, and all things
growing out of seeds are cause-born. The earth, water and
wind are season-born. Space and nibbàna exist independently
of kamma, cause and season. Of nibbàna, O king, it cannot
be said that it is perceptible by the five senses, but it is perceptible
by the mind. The disciple whose mind is pure, and
free from obstructions, can perceive nibbàna.</li>
</ol>

<p><a href="http://www.buddhanet.net/pdf_file/milinda.pdf" rel="nofollow noreferrer">http://www.buddhanet.net/pdf_file/milinda.pdf</a></p>
 8157: <p>Space does not exist independently of kamma &amp; cause. By kamma (action), space can be filled, such as filling a hole with soil. Or by cause, space can be created or removed, such as a volcanic eruption creating a cave with space but filling space in a crevice. Or when sickness blocks the space in the nostril. </p>

<p>The Lord Buddha said the realisation of space is conditioned &amp; not Nibbana. </p>

<p>Nibbana is dispassion; Nibbana is non-attachment; Nibbana is the destruction of craving; Nibbana is the absence of greed, hatred &amp; delusion. Therefore, a mind abiding in Nibbana can walk &amp; talk. Where as a mind abiding in space cannot walk or talk. That is why the Buddha rejected the dimension of the infinitude of space as Nibbana; because the dimension of the infinitude of space is limited, bondage, conditioned &amp; not freedom.  </p>

<blockquote>
  <p><em>One discerns that 'If I were to direct equanimity as pure &amp; bright as this towards the dimension of the infinitude of space and to develop
  the mind along those lines, that would be fabricated'. MN 140</em></p>
  
  <hr>
  
  <p><em>And what is the space property?... Anything... that is space, spatial... the holes of the ears, the nostrils, the mouth, the
  [passage] whereby what is eaten, drunk, consumed &amp; tasted gets
  swallowed, and where it collects... MN 62</em></p>
</blockquote>

<hr>

<blockquote>
  <p><em>In the course of the future there will be monks who won't listen when discourses that are words of the Tathagata — deep, deep in their
  meaning, transcendent, connected with emptiness — are being recited.
  They won't lend ear, won't set their hearts on knowing them, won't
  regard these teachings as worth grasping or mastering. But they will
  listen when discourses that are literary works — the works of poets,
  elegant in sound, elegant in rhetoric, the work of outsiders, words of
  disciples — are recited. They will lend ear and set their hearts on
  knowing them. They will regard these teachings as worth grasping &amp;
  mastering. In this way the disappearance of the discourses that are
  words of the Tathagata — deep, deep in their meaning, transcendent,
  connected with emptiness — will come about. SN 20.7</em></p>
</blockquote>
 254: <p>What do you mean by "realize"? See the <a href="https://www.wisdomlib.org/definition/%C4%81k%C4%81%C5%9Ba" rel="nofollow noreferrer">definition of <em>Ākāsa</em> here</a>, which begins,</p>

<blockquote>
  <p>'space', is, according to Com., of two kinds: </p>
  
  <ol>
  <li>limited space (paricchinnākāsa or paricchedākāsa), </li>
  <li>endless space (anantākāsa), i.e. cosmic space.</li>
  </ol>
  
  <p>1) Limited space, under the name of ākāsa-dhātu (space element), belongs to derived corporeality (s. khandha, Summary I; Dhs 638) and to a six fold classification of elements (s. dhātu; M.112, M.115, M.140). It is also an object of kasina meditation. It is defined as follows: "The space element has the characteristic of delimiting matter. Its function is to indicate the boundaries of matter. It is manifested as the confines of matter; or its manifestation consists in being untouched (by the 4 great elements), and in holes and apertures. Its proximate cause is the matter delimited. It is on account of the space element that one can say of material things delimited that 'this is above. below, around that' " (Vis.M. XIV.63).</p>
  
  <p>2) Endless space is called in Atthasālini ajatākāsa, 'unentangled', i.e. unobstructed or empty space. It is the object of the first immaterial absorption (s. jhāna), the sphere of boundless space (ākāsānañcāyatana). According to Abhidhamma philosophy, endless space has no objective reality (being purely conceptual), which is indicated by the fact that it is not included in the triad of the wholesome (kusalatika), which comprises the entire reality. Later Buddhist schools have regarded it as one of several unconditioned or uncreated states (asankhata dharma) - a view that is rejected in Kath. (s. Guide. p. 70). Theravāda Buddhism recognizes only Nibbāna as an unconditioned element (asankhata-dhātu: s. Dhs. 1084).</p>
</blockquote>

<p>So maybe people do perceive space: both limited space (in ordinary perception) and unlimited space (as an object of meditation).</p>
