> A lot of millenials have learned a lot about the existing financial system due to Bitcoin, even if it was initially to make a quick buck, and I suspect there's no way back to fiat for a lot of them.

This is exactly the kind of one-sided perspective that makes me very sceptical. No, they didn't 'leave fiat' in any way, and they never will. At best they can hedge against it a little. But while that might be personally profitable, it is not clear at all whether it is a net benefit; the main problem of western economies nowadays seems to be too tight monetary policy, and crypto is tighter than fiat.