I don't know where this reasoning about bitcoin being worth $1M comes from. Somehow it seems impossible to me. So far, people don't have such a huge need for bitcoins. But if it's going to be in demand around the world, then probably 1M isn't fantastic.
It's still very hard to believe bitcoin reached the fantastic price of $1M, I don't know about the predictions that will come with a long time but it's likely that a lot of people will believe at this price because bitcoin availability is limited then that's what might be a higher value bitcoin.
Will the whole world evolve to bitcoin? I think it will be very difficult for a country to maintain their fiat as a medium of exchange and bitcoin may only be an alternative option, but then again I believe in the rapid change of bitcoin.
It hasn't reached it yet, but I bet that it will one day, because that's the natural trajectory it's taking. I mean even if it doesn't reach it quickly and right away, that just means that we are going to end up seeing something a bit different on the long run, it's going to be just a boring situation with a higher inflation and dollar will devalue just as usual and just like gold goes up, bitcoin will go up and that will make it above 1 million dollars anyway.
That's the boring possibility and it still does, but the fun possibility is that it will happen within the next 5-6 years, how? Well we will have a big halving next year, and I believe it will go up after that, then 5 years from today, we have another one, so between the one next year and the one after that, it will go a lot higher and it could end up being over a million.