Ah, it's a number that I got in a calculation (for a projected scenario), not a coin that I may or may not have.
TL;DR: too high a price of bitcoin (in the multiple millions) will result in a drastic increase in global millionaire numbers (if hodlers do not sell en masse), which is unlikely, therefore the price in the multiple millions is unlikely.
My calculated upper bound price of btc that does not affect the total number of millionaires too much is about $1mil/btc.
You are missing a number of factors. There will be the first trillionaire not too long from now. The global population is steadily increasing. Global economy growing. Inflation isn't going to stop anytime soon. To name a few.
It's a given that the number of millionaires will grow by an order of magnitude within our lifetime. Heck, what even is a million these days? Unless you move to a shithole, or resign to a very modest life you won't really be getting anywhere.
How much of that money will land in Bitcoin is another story. But "too many millionaires" is not an argument against it. I don't see multi-million BTC as implausible in 2030-2050 and certainly not beyond.
Sneaky sneaky.