Zimbabwe did not choose a currency with a very limited suply. They choose dollars. Rest of what you said does not make sense at all. Nobody will sell a single bitcoin if bitcoin seems to be the dominant currency. Give me a single sane way bitcoin could replace fiat.
I don't like this your spirit, it means you can't understand what I write.
I may be wrong, but you are being a bit too presumptuous in your statement for my taste.
You say: nobody will sell bitcoin if that's the dominant currency.
That's in part true.
But think for a moment: why are people selling $ or ? THESE ARE DOMINANT CURRENCIES.
The only problem will come when there will be so few shops around accepting fiat currency, that nobody will want to give you some BTC in exchange for fiat: what the hell will they do with that currency?
Not your business: there are always people less clever than others that remain stuck to something even when it's going to be completely useless.
There are people still using light bulbs, just because a led light is more expensive than holding that light bulb.
They can't even understand how much electricity they pay every year with that bulb.
Other people can't even believe you can have an electric scooter and pay 1.3 for 100 Km travel.
There will probably be some communities that will want to remain on paper currency because "fuck government wants to spy our every move with online transactions! I won't allow them!" in example (I heard a lot of this).
So, dude, it's ok, I may be wrong, but what I write has a sense, maybe you can't understand it fully now, but you will in the future.
Also, the fact that Zimbabwe has choosen dollars doesn't change a bit my reasoning: one day, some unlucky retarded guy will still have 900 betatrizillion zimbabwe dollars, will go to the bank and the bank will give him 5$ for that. Or more possibly, 5 uBTC.
And those may be his savings of one life.
That's exactly what will happen with Bitcoin: somebody is first, somebody is last. The last ones will cry.