But I mean come on, they're Microsoft. If they really wanted filesystem access to be efficient across systems, we'd have it by now. Although convenient, I doubt that's on their list of primary motivations for doing this.
Here's one of the developers saying it is hard back in the WSL days.
https://github.com/Microsoft/WSL/issues/873#issuecomment-391...
The reason makes sense to me, but I'm not an expert. Maybe you could expand on why you think they could do it but chose not to?