If Apple's Mac business was it's own business, it would be in the Fortune 500.[1] I agree that they're pushing iOS hard, but I think as long as revenue is as strong as it has been, this new Post-Jobs Apple won't be getting rid of Macs.
No reason they couldn't port XCode to iOS, and given the nature of skunkworks projects in Apple, this may have already occurred. Plus they also have their current installed base of Macs that can still be used even if Apple stops development of new features for macOS while they transition the tools to iOS.
FWIW, the MacBook Pro (late 2016 model with TouchBar) that I'm typing often gives kernel panics on attempting to resume from sleep, but on my new ThinkPad T25 (running NixOS, of course), suspend and resume work OOTB and I've yet to see a problem occur with it.
The GNU+Linux world is always changing, and Linux's hardware support gets better every year. I get the joke-- I've lived through suspend/resume hassles on laptops running Linux before, compiled the custom `tuxonice` kernels, etc. But no manufacturer who sells Linux computers has to ship laptops that have any trouble with suspend/resume, and my luck has been pretty good with a lot of recent, formally non-supported hardware I've tried.
Seems unlikely considering the huge amount of APIs shared between ios and macos that would make porting a working simulator a herculean task. CoreAudio, AVFoundation, Metal, Mach kernel APIs and ports, XPC, CoreGraphics, CoreAnimation, etc etc etc