The Studio is a closed, non-upgradable box, it is a more of a Prosumer system with workstation-like performance (M1 Ultra).
High end professionals, the very people Apple designed (and priced) the Mac Pro for, need more memory and expandability and workstation grade performance. It was designed when they knew they were going to move to their own silicon, so I don't see it changing in any way other than having an Apple Silicon option. (Yes, I think they will continue to offer it with Intel XEON.) What that ASi looks like, I don't know? Maybe it's an Ultra (or two), but without on package memory? Maybe it's a discrete CPU, an "X1", with up to 64 cores that absolutely kills everything on the market? Will be interesting to find out though.