If you already invested in early years, got fortune and your financial status now is like financial free, you will never return to fiat system that is very understandable.
For new investors, who are still practicing with investment, storage and waiting for profit, their complete exit from fiat system will need time like several more years, some more market cycles. I believe that senior Bitcoin investors with good profit from their investments will not want to return to fiat system that is controlled by governments and central banks.
Governments and banks can seize your money in bank accounts but they can not seize your bitcoin in your non custodial wallets if you don't do any illegal things.
To be in such a way of thought is to have so much BTC that you don't have to worry of when and how much to swap back to fiat if needed.
It's a hard thing to master, and I do think that one should anyways have some fiat prepared for the black days as a caution measure, - but BTC, surely, is the best store of value out there.