OP seems to think that money (he means fiat) must go into bitcoin. This is a fallacy. It is the value that has to come into bitcoin.
The value is in the minds of the actors. First they value something, then they change and value something else.
And where does it come from? Maybe from fiat money, maybe from other things that functions as value stores, like houses.
They go hand in hand, the more fiat in BTC - the more the masses deem it with a certain
value.
The more '
Value' in Bitcoin, in terms of adoption of currency like features, the more fiat currencies go in to bit coin.
It's a two way street.