peter todd, sourced and mathematically argued quite convincingly, "Lightning can probably support low hundreds of millions of users with current technology."
#681498 buried in a good conversation btw if you care
another one from alex bosworth, also buried in some wider context which is worth a read
A common objection to this is,
"but there are more than 100 million people! So we need a scaling softfork. If that broadens the attack surface, it's just a price we have to pay. Otherwise bitcoin will become a custody solution only for the very rich, with banks able to rug pull and fractional reserve just as they did under the gold standard, and a typical user will be at their mercy. Bitcoin will be meet the new boss same as the old boss. Goodbye to our dreams of freedom."
So here's my 2c about that.
the masses aren't stupid, and you can't chalk it all up to laziness either.
physical security is hard, really hard.
and if you keep your hardware wallet seed phrase in a bank safe deposit box, how different is this really from just keeping your utxos as an IOU in the bank?
OK the bank doesn't have the device pin number so it's different. You could also do multiple safe deposit boxes in different banks, and maybe throw in one buried in the backyard or with your lawyer, so it's different.
But now you are trusting the hardware device manufacturer to not backdoor the random number generation. You are trusting the M-of-N quorum to not screw up and betray, even picking a good M and a good N is hard.
OK, figure out hte M and the N. Make your own hardware wallet using an esp32 chip. Or maybe you should use the trezor mostly open-source thing with a secure element ("tropic square")....... Yeah but what % of people will actually do the analysis, the homework, figure out the maze of security tradeoff and then make a rational decision for achieving the best security/convenience tradeoff? I think it's well under 1%.
And that's how you go from 10 billion people to 100 million custodians in a well distributed "custodians are family/small businesses" plus a few whale custodians in banks/exchanges, lightning network scenario.
Scaling softfork?
YAGNI.
Don't let scaling or vaults be a trojan horse for those who would shitcoin on bitcoin, for the benefit of a few insiders at the cost of a broader security surface for all.