Adoption as a global currency, where all bitcoins were mined and purchased
Discussion
That would be option 3 I mentioned above. Bitcoin would have no price at that point. It would instead be what all other goods are priced in. You would no longer be able to buy it with dollars, since the dollar would be dead, so it would not have a dollar price.
I asked chat gpt and it told me 1 BTC would worth 60 million
It can't be worth $60m if dollars no longer exist.
Now, if you want to estimate purchasing power compared to current USD value, you would need to look at total currency supply today divided by the expected supply of Bitcoin that could be used as currency (that is, Bitcoin that isn't lost/burned), and also estimate growth in productivity between now and this hypothetical date.
In other words, it would be not much more than an educated guess. $60m/Bitcoin doesn't sound unrealistic, though.
That's what I asked chat gpt to do, including derivatives and black market