Gold will exist in 20 years, BTC not sure
But what will the value of gold be in 20 years?
The immutable value of shiny gold in 20 years will be the same as 1000 or 2000 years ago.
It will get you food, clothing, shelter, and intimate companionship.
Gold is proof of work, being born in a quasar or other extreme cosmic event.
SHA256 and ECC will be broken and forgotten long before we can duplicate the power of a supernova.