LOL. I mean, it's inevitable, right? Someone will almost certainly do this. The CPU in the Pi is also going to be a limiting factor, but I'm looking forward to someone posting Pi + RX 5700 XT performance results. "I bought a $50 Pi, then attached a $375 GPU to it via a $25 adapter setup!"I'm waiting for someone to use the Ubuntu image and compile a custom kernel with AMD GPU support.
Then, you could put a real GPU in there. Even though it'd be limited by just a x1 PCIe 2.0 link, I'm sure even a RX 550 would still run circles around the Pi's integrated VideoCore GPU!
The Pi's GPU is definitely one if its weakest aspects, in the current generation.