I just can't agree, the M1 doesn't punch above it's class in multi-core work, and that's what Pro machines need the most. My M1 MBA really isn't fast enough for what I do and I'm not counting myself in that Apple Pro class. (It could be the lack of cooling that is coloring my opinion, but until I try another machine, it is what it is...)
I'm not saying Apple can't do it, I bet they can, but I'm saying it'll cost a lot with not much benefit, and I just think Apple might think twice about it because of that. in other words, what's the ROI for designing/implementing their own chip when there's already chips that can do the job. And it's not like that level of machine needs a hardware update every year, just look at the history of updates for the Mac Pro...