I like the sandboxing model but virtual machines add way too much abstraction and overhead. Apple's approach is really good here IMO, as a user I need to be able to do things like select any file at any time, and it will under-the-hood add that selection to the sandbox
I wonder how much overlap exists between the security fanatics and those who post the "why my OS laggy??" threads around here about once a month.
The collective brain damage from a 500ms+ start menu has probably already placed us into a fatal death spiral.
Not saying you can't make an OS secure AND fast, but it definitely seems challenging if you also want to keep support for applications written 20 years ago.
VM technology currently adds a lot of conceptual and computational overhead in most cases but there are examples of it being integrated more seamlessly. WSL 2 is a good one.
