user121588: Bitcoin verifies about 220 million transactions a year. Even when using Lightning, wouldn't I want to verify my Bitcoins at least once a year on the Blockchain? With 8 billion humans verifying once a year, wouldn't it take on average 40 years to get verified in the blockchain? What if you're forced to close a Lightning channel?
Wouldn't this make the Bitcoin use not secure anymore?

user208: A lot depends on how you define "scalable".
If your question is: do we have ready-to-go technology, which without further on-chain Bitcoin protocol changes, is sufficient for making everyone on the planet to have personal Lightning channels on Bitcoin, the answer is almost certainly no (I'm not an expert on Lightning).
But scalability is generally understood to be more a question of "how do resource requirements scale in function of usage", and for that, Lightning is a significant improvement compared to purely on-chain payment transactions (while coming at the cost of additional assumptions like liveness: the ability for participants to get their settlements timely included on chain). That doesn't mean further technological improvements won't be necessary for further growth.

user81940: Yes.
But with the coming  taproot upgrade and schnorr signatures we can create a single Bitcoin tx that is n - of - n multisig which enables us to do multiparty channels with n participants in 1 transaction. So if you take n=40 we can onboard 8bn people in 1 year. If you choose n=480 we can do it in 1 month. So let's keep fingers crossed for that Bitcoin upgrade.

121588: <p>Bitcoin verifies about 220 million transactions a year. Even when using Lightning, wouldn't I want to verify my Bitcoins at least once a year on the Blockchain? With 8 billion humans verifying once a year, wouldn't it take on average 40 years to get verified in the blockchain? What if you're forced to close a Lightning channel?</p>
<p>Wouldn't this make the Bitcoin use not secure anymore?</p>
 208: <p>A lot depends on how you define &quot;scalable&quot;.</p>
<p>If your question is: do we have ready-to-go technology, which without further on-chain Bitcoin protocol changes, is sufficient for making everyone on the planet to have personal Lightning channels on Bitcoin, the answer is almost certainly no (I'm not an expert on Lightning).</p>
<p>But scalability is generally understood to be more a question of &quot;how do resource requirements scale in function of usage&quot;, and for that, Lightning is a significant improvement compared to purely on-chain payment transactions (while coming at the cost of additional assumptions like liveness: the ability for participants to get their settlements timely included on chain). That doesn't mean further technological improvements won't be necessary for further growth.</p>
 81940: <p>Yes.</p>
<p>But with the coming  taproot upgrade and schnorr signatures we can create a single Bitcoin tx that is n - of - n multisig which enables us to do multiparty channels with n participants in 1 transaction. So if you take n=40 we can onboard 8bn people in 1 year. If you choose n=480 we can do it in 1 month. So let's keep fingers crossed for that Bitcoin upgrade.</p>
