I very much agree with the notion that Bitcoin will improve fiat first, then replace it entirely. It follows the Store of Value -> Medium of Exchange -> Unit of Account pipeline. Improving fiat by acting as a rails is the Medium of Exchange part. That will bolster the Store of Value use case for Bitcoin and lay the foundation of the Unit of Account stage (replacing fiat completely).

What I'm unsure about is how to correctly implement a stablecoin. Should it be via stable channels? A separate asset? An onchain asset? Perhaps the point is that there really isn't a good way to implement stablecoins. Maybe a combination of this fact and the fiat becoming more and more useless due to the actions of governments and central banks will naturally lead people to the Unit of Account stage.