Right. Apple is adding more and more security features from iOS into macOS. But, people are going to complain about that too.
> Other operating systems can run in _parallel_ with iOS
Absolutely, but there is a performance hit and memory management becomes an issue. You still need a host OS as well to unify the UX. Also, there needs to be some way for IPC between the applications of different OSes.
> Microsoft implemented WSL
WSL has networking and memory management issues. WSLg sort of works. Its architecture is wild [1]. Display scaling is terrible though. IPC between Windows and WSL guests is limited.
WSL 2 was released in 2020 and it still has issues. It's not a simple problem to solve.
Microsoft has also gone from WinRT, UWP, WinUI, MAUI, and now WinUI 3 trying to unify application development [2]. Again, it's not a simple problem to solve.
I think the only OS that has actually unified application development across all form factors is Android/Chrome OS. But, people complain about how limited Chrome OS is.
[1] https://github.com/microsoft/wslg?tab=readme-ov-file#wslg-ar...