They should have looked at Plan9 and the Rio window manager there.
I don’t know how GPU acceleration would have fit in, but I bet it would have been trivial provided the drivers were sufficient.
All of Rio in Plan9 is 6K lines of code and it’s a more powerful display protocol and window manager (all of the fundamentals are there but none of the niceties) than anything else I’ve ever seen.
The defacto way to remote into a Plan9 system from any OS even today is to use a client side program which implements it all the same way Plan9 does.
