Comment by bombcar

The problem is that the M1 chips foretold the doom of the Mac Pro unless they could figure out some way to do something that you couldn't do with a Mac Studio - thunderbolt is so good that it's hard to justify anything else.

If they had done more with NUMA in the M series maybe you could have a Mac Pro with M5 Ultras that can take a number of M5 "daughter cards" that do something useful.