>So consumer GPUs top out at 16GB (5090 currently)

5090 has 32GB, and the 4090 and 3090 both have 24GB.

It will be interesting to see the specs on an m5 ultra. Probably have to wait until WWDC at the earliest to see it though

Hard to get 6000+ bit memory bus HBM bandwidth out of a 512 or 1024 bit memory bus tied to DDR... I think it's also just tough to physically tie in 512 gigs close enough to the GPU to run at those speeds. But yeah, I wish there was a very competitive local option, too, short of spending $50k+.