Q:

Does question's upvote need to have 5 points?

Well, on one of the networks, I've gained almost all of my rep. using only 1 question.  What's more, I've seen about 10k users, which have only asked something newbie question 10 years old (and have almost no activity after that  and no answers), and have about 10+k rep. (btw, my respects to them, just mentioning several examples:  this or this or this)
I think, the overall result, is misleading about user's real skills.
Why it's 5 points? I think i.e. 2 points could be more realistic.
to be a trustworthy site, you should have more reliable rankings - that's what i mean. and When i see 10K people, then now i have to put an detailed effort in it (search his questions and answers), if he is just a baloon, or a programer, who has contributed 1000 answers...

A:

The SE could have a more exact system about measuring the usefulness of the posts of a user. However, I think I can see a reason why they don't tune the reputation system continuously: having clear, simple, and forever unchanged rules works as a source of trust for us. In other words, we always know what is the worth of what we posted here.
The cases you mention do exist, and I agree they may be a little bit unjust. But they are few.
And don't forget also the view of the SE. They want to produce many hits, thus useful content on their sites. The single questions got to +2000, thus they attracted a lot, mainly satisfied visitors, are extremely useful from this view. It doesn't matter that they had only luck and thus they have found somehow the top in a common google search list.
Also you can have some similar luck. For example, my most upvoted post was a trivial, single-sentence answer, for which I don't really have reason to be proud. My other posts, in them I invested a lot effort, and I think they were really, really good posts, remained on +1, +2 score. I am not satisfied with that, but this is how our world works. Consider if you start a company, you invest years of work in it, and finally it can be busted, despite that you were really good.
But there could be semi literate high school dropouts, and sometimes they can start such companies like Facebook or Microsoft. Only because they had luck.
Luck is an inherent component of our world to achieve success. There is no guarantee that you will be lucky, but we all have chance for that. What is going on in the real world in big things, the same is going only here, in small sizes. It is not the fault of the SE.

