After being excited for VR for so long, now that it's finally here it turns out what I actually want is the ability to do all this with my mind whilst laying in bed rather than having my eyes open and exercising.
A couple of years ago, an admin at Hacker News asked those of us who are just reading to log out because their system is architected in such a way that logged in users use more resources than anonymous ones. So, if you're feeling altruistic, log out of HN!
Probably because it's the wrong tool for the job. If you want to play games, a Mac is easily one of the worst ways to do that.
The eGPU method of bolting functionality onto a platform which doesn't want it is only neat on a technical level at best. It is essentially the world's biggest dongle.
I agree with pretty much everything you've said except the part about overlapping windows. I find Sticky Previews immensely helpful in Windows and sorely miss it when using other operating systems.