Displays are still bandwidth killers today, we kept scaling them up with everything else. Today you might have a 4k 30bpp 144hz display and just keeping that fed takes 33Gbit/s purely for scanout, not even composing it.
I love the monitor, it's sharp and clear and almost kind of HDR a lot of the time, but the fact that it has a bunch of USB 3.0 ports that only get USB 2.0 speeds because I don't want choppy 30Hz gaming is just... weird.
Consequently almost nothing actually renders at 4k. It’s all upscaling - or even worse your display is wired to double up on inputs.
Once we can comfortably get 60 FPS, 1080p, 4x msaa, no upscaling, then let’s revisit this 4k idea.
So yes you get 4k pixels lit up on your display, but is it actually a better image?
And yes there may be high end hardware which can handle it, but the sw still made design choices for everyone else.
There are also image algorithms which are not as amenable to GPUs which are now impossible to compute effectively.
It doesn't help if your crossbar memory interconnect only has static priorities.
I think partial refresh capability only came with some optional extensions to DisplayPort.