You'll need large economies of scale to do better than GPUs, and you'll still have all the same problems of memory IO, packaging, and heat removal. Transistors

You'll need large economies of scale to do better than GPUs, and you'll still have all the same problems of memory IO, packaging, and heat removal. Transistors that aren't in use cost almost nothing. This is a big part of why RISC didn't win and today the largest server chips in use in datacenters are still mostly compatible with an 8 bit part from the early 1980's.