Nowadays the WSL basically made Windows my all-in-one development environment. My stack is WSL, docker and Jetbrains IDEs (but the latter is just a matter of personal taste). I haven't touched my Linux desktop in over a year.
Personally, for my workflow, I no longer see a benefit in running a cloud IDE. But maybe that for junior or aspiring devs a cloud IDE will make it much more easy to get started.
But now, thanks to WSL I have turned that around. I now run Windows so I can run the windows-only debuggers natively, and still have all the unix tools available through the WSL CLI.
Admittedly I do not do much embedded development anymore, but I'm pretty sure I could launch Windows ICD tools from the WSL CLI.
I think it’s never going to happen. It’s the complete antithesis of everything that Apple stands for as a company.
The easiest thing would probably be to virtualize the OS X kernel.