so just run the math on mining costs and you have the answer
From what I understand OP wants a prediction for the future price .. no matter how far that future is?
If so, we cannot really predict how energy price will evolve, how the semiconductors and ASICs will evolve... hence, while your logic can be okay for short term, it cannot have enough data for way in the future.
Is there a price that BTC is limited to?
It's
very hard to tell. I've seen answer that fiat is unlimited. That's correct, we don't know where inflation can get us. But I don't think that a huge percent of world fiat will ever get locked into Bitcoin, since if that would happen, world fiat would simply get replaced with bitcoin (and that would be one step farther than backing fiat with bitcoin).
So, like some memes show, at the point bitcoin would get to worth a huge amount of money, there may be that there will no longer be that kind of money.