Isn't the Mac Studio the new trash can? I can't think of how a non-expandable Mac Pro could be meaningfully different to the Studio unless they introduce an even bigger chip above the Ultra.
Indeed, and tbh it really commits even more to the non-expandability that the Trashcan's designers seemed to be going for. After all, the Trashcan at least had replaceable RAM and storage. The Mac Studio has proprietary storage modules for no reason aside from Apple's convenience/profits (and of course the 'integrated' RAM which I'll charitably assume was done for altruistic reasons because of how it's "shared.")
The difference is that today users are accepting modern Macs where they rejected the Trashcan. I think it's because Apple's practices have become more widespread anyway*, and certain parts of the strategy like the RAM thing at least have upsides. That, and the thermals are better because the Trashcan's thermal design was not fit for purpose.
* I was trying to fix a friend's nice Lenovo laptop recently -- it turned out to just have some bad RAM, but when we opened it up we found it was soldered :(
