GPU Sharing Between VMs and a Host

This seems like the final technology in containing and categorizing different PC uses into different virtual machines, while still having good feel even in contained things. If set up right you can have a seamless experience tabbing between a host system and virtual system, and you can do whatever you can normally do in either one! Wanna use linux, but Discord hardly works and you like to play Halo too much to figure out how to dodge it's anti-linuxcheat system? Now you can switch to linux and just run a single script to pull up a fully gaming capable (near bare metal performance) windows system right inside a linux system. Idk about y'all but as far as cool technology to talk about in here goes... this definitely fits for me. I feel like if more people knew this was something you could do relatively easily (if you enjoy tinkering with your OS) with MOST consumer Nvidia cards (20 series and older), Linux would've already passed 5%. What do y'all think about it? The ability to, off a single consumer CPU and GPU, host several acceptable, mid-performance, cloud accessible (or just virtually separate, locally accessible) PCs?