The 27" models have traditionally used off the shelf socketed CPUs though, which is unusual in AIOs. Regular 27" models use desktop i9s and the Pro uses a desktop Xeon. Both can technically have their CPUs upgraded even if opening them is a pain.

Thank god for them being thin, I actually had to throw away my 2013 iMac because it was just unbearable reading my emails with x-ray vision and noticing just how thick it is.

Parent is referring to Mac Pro (the desktop).

I blame Apple's product line branding for this confusion. I make the same mistake all the time.

The M2 isn't out yet, so we don't know what it can beat. But core for core, Apple Silicon has the best performance by a wide margin with much lower power consumption than any x86 part (because while we weren't looking, RISC architecture really did change everything). Plus, its on-chip memory will equate, in a Mac Pro-like system, to gigabytes of L3 cache. Add on to that that Big Sur and later are specially optimized for the Apple chips, meaning that performance cores won't be burdened with the background tasks the OS performs, leaving 100% of their throughput available for user applications. So yeah, core for core the Threadripper will get smoked, and I wouldn't be surprised if an M2 with half the number of performance cores as a Threadripper has remains competitive with the TR for representative tasks (such as video editing, rendering, and encoding).

I do not see why not - performance of Apple processors is insane.