Have you looked at the Mac Pro Rack version?

It's overkill because they preserved nearly every aspect of the Intel version when switching it over to ARM, even when those design elements no longer made any sense. It's built around cooling GPUs that aren't supported anymore, has a power supply with about 4x more wattage than the system will ever draw, and has way more physical I/O than the new silicon is actually equipped to support, requiring heavy oversubscription via expensive mux chips.

IMO that points to the Mac Pro being on its way to retirement in favour of the Studio - they would have made more of an effort if it were sticking around.

I've been keeping up with Apple since 2004 when I was in high school. Even back then, a lot of Mac fans wanted Apple to release an "xMac": a Mac with one or two expansion slots, user-serviceable, and priced less than an entry-level Power Mac G5/Mac Pro, somewhere in the $1,499 range. Yet Apple never delivered. Sure, the Mac Mini was introduced in 2005 and has remained part of Apple's lineup ever since, and there's also the 2013 Mac Pro and the modern Mac Studio, but these lack expansion slots.

Sadly I think it's even less likely we'd have something like an xMac today. Consider the MSRPs of base-level Mac Pro models from 2006 onward. During the cheesegrater days, entry-level Mac Pros were available in the $2000s. The "trash can" Mac Pro had a starting MSRP of $2999; more expensive than the cheesegrater models, but still not a gigantic leap from its predecessor. But when Apple released the 2019 Mac Pro tower, the MSRP took a dramatic leap to $5999, pricing out many people who had the budget for a $2999 or even $3499 computer. As a user of a 2013 Mac Pro, I would've bought a 2019 Mac Pro in a heartbeat in 2019 had Apple maintained a $2999 entry price. The ARM Mac Pro is even higher priced at $6999.

The message from Apple for over 20 years has been loud and clear: Apple does not want to sell an affordable, expandable, user-serviceable desktop, and Apple at times doesn't always look committed to expandability and user-serviceability. I expect the Mac Pro to be unceremoniously discontinued, though I could get shocked like I was in 2019.

I bought a G5 Pro back in the day, the last with the Motorola chips. The thing was a beast, even though the hardware was superseded by the intel architecture. I used it as my rendering rig throughout university, and the machine kept chugging along for years and felt perfectly fine and snappy all the way up to when OSX dropped support for it.

I ended up gutting the case and building it into an ATX machine, and eventually sold it to a friend. But it was a fantastic computer.