At some point this is going to make Firefox unusable
I've been flirting with the idea of trying out USB external graphic cards, which can be done via the USB protocol. Full PCI USB card passthrough already works in Qubes, so technically, this "should" allow full-blown graphics in Qubes in terms of graphic card availability. In regards whether a higher version of OpenGL is possible, I suspect without knowing for sure, that this is requiring a graphic driver to tie to? So I speculate, if USB external graphic card becomes available, then, so too OpenGL "should" work in higher versions?
The other means I know of that works is to pass-through the graphic card directly to Xen, bypassing Qubes entirely, essentially exposing dom0 and Xen. Currently this method works, unless it was broken again. It's just that there is a huge security "hole" in Qubes in order to get it to work.
Essentially, the dom0/xen exposed example shows a working graphic card, seems to be the missing link to make everything tie together, if I'm not mistaken.
Now if you can get USB 3.1 type 2 with 10Gbit/s connection working, then you can get some pretty decent graphics. If you can get Thunderbolt working through USB 3.1 type, then you have access to some 40Gbit/s (they merged recently, although not all USB 3.1. have thunderbolt support yet).
Regular USB 3 only offers 5Gbit/s, so it's a bit of a downside for heavy graphics.
It'd be cool if someone can test this out, I've been thinking of doing it for many months now, but I've simply never got around to it. It's also a bit expensive, at least currently. It's best to investigate and research before throwing money at something like this, it may not work after all.
But all things considered, USB passthrough already works, so it "should" work, no? Especially so if you get thunderbolt working in USB 3.1. type 2. Also thunderbolt is only merged in USB-C ports (the new modern standard only slowly appearing atm), but not all USB-C ports support thunderbolt.
The question is though, would this work at all.