Someone above mentions exporting a video stream to handle remote sessions. I think that's actually a strong contender for a new User Interface system, but it discusses nothing about how that actually happens.
It the GPU exports an MP4 video stream that can be delivered directly to any display (local or remote) that deals with the last connection bottleneck. It's a standard, its ubiquitous, and its implemented in hardware. The return channel for user interaction needs to be done, but that doesn't have the performance issues that the presentation does.
The other piece of the system that needs to be handled is the API for the interface to the GPU hardware. A contender for that seems to be an API tied to EGL ES (if I read the acronyms right), and there should be others. That assumes the Khronos Group is doing something useful there. How many implementations are there of EGL ES to GPU hardware drivers?
The layer in the system between the user applications and the hardware interface is the place where QT, GTK, Windows graphics api, and all the other graphics toolkits go. Those toolkits shouldn't care too much about the hardware details, just the published capabilities of the GPUs.
Just some thoughts