I don't think Apple cares much for those people, they can buy the Mac Pro or a PC if they really need the GPU power.

eGPUs can be a nice addition, but I doubt Apple will release an official eGPU system. You're already limited to AMD GPUs after the clusterfuck of a fight Apple and Nvidia had, and I doubt Intel's Xe lineup will receive much love for Apple right after the Intel CPUs have been cut from Apple's products.

Honestly, for the kind of work that does need an arbitrary amount of GPU horsepower, you're barking at the wrong tree if you buy Apple. Get yourself a Macbook and a console or game streaming service if you want to play video games, and get yourself a workstation if you want to do CAD work.

I don't think the work Apple would need to put into a GPU solution would be worth it, financially speaking.