Well I can't say I'm at all surprised. I'm used to ARM chips from running Raspberry Pis, which are now getting good enough to run as desktop machines, and the RISC instruction set has been proven to be far better for performance and power consumption in the long term. So from a technical standpoint, it makes sense.
The obvious difference is that a Pi costs next to nothing, and you can buy bundles of them. The obvious drawback is it doesn't run old Windows software that you don't have the source code for, and I suspect a lot of people who got Macs because they could also function as PCs, and Unix boxes and hence "do it all" are going to be stuck for this. Apple may think that 20-year old software is obsolete, but many people in the corporate world rely on this sort of stuff, and will be far more cautious about moving to MacOS if backwards compatibility completely flies out of the window.
As a longtime Windows critic, I've got to say Windows 10 is pretty good these days, and I think only hardened Apple fanboys would disagree. It's the complete opposite to MacOS - anything that ran the first build of Windows 10 will run the current build 5 years later without any issues whatsoever. The hardware is orders of magnitude cheaper, there's a better variety of components, and stuff just works these days. Sure, you don't get a Unix command prompt out of the box and I've never quite found the time to learn Powershell and Mingw is not quite the same ... but most people don't care about that. I'm already starting to look at alternative DAWs to Logic, such as Bitwig. I'm not really bothered which OS it runs at this stage, except that I am pretty confident that both Windows and Linux will support the system for years to come.
It's been a good 10 years with Apple, but I can now picture myself jumping ship at some point. As someone who tinkers around with hardware and software quite a bit (kind of the reason I ended up here), I really want to see Linux pick up a bunch of ex-Mac users so it can have a better desktop experience. It's already getting much more support for games, and unlike MacOS your not-so-ancient NVidia card will still work!
As for Big Sur's attempt to look more like IOS - jeez, is this the new Windows 8?