If 20% of all BTC has been lost, that would mean that...

https://www.investopedia.com/news/20-all-btc-lost-unrecoverable-study-shows/

https://www.nytimes.com/2021/01/13/business/tens-of-billions-worth-of-bitcoin-have-been-locked-by-people-who-forgot-their-key.html

https://decrypt.co/37171/lost-bitcoin-3-7-million-bitcoin-are-probably-gone-forever

If this is true, and BTC someday becomes the world's reserve currency, replacing the 200 trillion dollars of currency in circulation around the world, that would imply that the final value of one BTC could be as much as around 10 million dollars, nominally speaking, in today's money.

Which would make each sat worth about a dime.

And of course the shrinkage, while I'm sure it's slowed dramatically as BTC has increased in value, hasn't stopped altogether. And even after it arrives at its final destination, and even if that destination is 10 million usd, it won't stop even then. Even if BTC replaces all other currency, the deflation, although slowed, will never stop.

Those are kind of sobering thoughts. And that's also assuming that its evolution from this point forward is smooth. While I'm very optimistic about BTC's ultimate success, I think a big part of that success will be surviving yet another global financial crisis, which I believe will be far worse than the first one. I believe BTC could suffer horribly in the short term during such an event, but recover dramatically when hyperinflation of fiat currencies finally sets in. I could easily see a scenario in which a global financial crash brought BTC to its knees, and cause the world to think it had failed. In such an event, we could see key loss like never before, even worse than the development phase when people took few precautions to protect them.

So ultimately it's anyone's guess how much value a single BTC could have. But it would seem that 10 million in today's dollars is a good conservative estimate, in the event that it eventually became the universal reserve for the world.

I write this as a word of encouragement, but also as one of warning. Along with the standard advice of not investing more than you're willing to lose, I would add to that, if such a time comes when people think BTC is dead, that may be your signal to guard those keys more tightly than ever before. Even if it returns to .10 per BTC, you continue to protect that BTC as if it were worth 10 million, because if hyperinflation kicks in, it could literally go from .10 to 10 million dollars in only a few short months.