Right now, for LLMs, the only limiting factor on Apple Silicon is memory bandwidth. There hasn’t been progress on this since the original M1 Ultra. And since abandoning UltraFusion, we won’t see progress here anytime soon either.
Have they abandoned UltraFusion? Last I’d heard, they’d just said something like “not all generations will get an Ultra chip” around the time the M4 showed up (the first M chip lacking an Ultra variation), which makes me think the M5 or M6 is fairly likely to get an Ultra.