You can in fact already do this (have Mac windows show up as separate floating windows in VisionOS instead of all being on the single MacOS window) using a third party tool called Ensemble:
The point is that this should absolutely be capable of being a power-computing extension for Mac, but instead it’s been relegated to a $3k personal theater that runs apps for some reason
https://github.com/saagarjha/Ensemble
This is what is looks like in action:
https://twitter.com/TheOriginaliTE/status/175125156764134634...
Disclaimer: I don’t know how well it works in practice because I don’t have a Vision Pro.