The onus is frankly on the suppliers of good and services to demand Bitcoin and reject fiat. That's how Thier's law works.

I'm happy to spend Bitcoin with Bitcoiners' businesses, but if Amazon started accepting it tomorrow I'm giving them any fiat I have, or am borrowing, until they stop letting me, or I run out and only have the Bitcoin.

Also, holding wealth is a function of money. The idea that it isn't is born of fiat having broken the money.