A couple of thoughts...
Leaving OS X with Catalina was bad form, as that meant that its expansive legacy ends on a low note (worse than Vista), and not a high one. While not once acknowledging the OS transition, none the less. I think they did it not out of any good reason or logic, but just to have a clean cut, so that they wouldn't have ARM Macs running both OS 10 and OS 11, that it wouldn't be left on 10.17 or 10.19, etc.
I think moving to ARM is ultimately a good move (as it will put an additional dent in Intel's already declining market share), but could have been executed in far more agreeable ways.
If you look closely, you can see that there is no "Memory" tab in that About This Mac window like there used to be. So my predictions are that, matching in line with Apple's vision of an ideal (locked down) computer, all ARM Mac memory will likely be soldered in, dGPUs will be phased out, and maybe only non-volatile storage options will remain as a user accessible component (going off of the window alone).
More than likely, Hackintoshes will no longer be possible, and Apple will exert even greater control on anything to do with their ecosystem, including their software, which will likely nag you for an Apple ID even more now. - On a related note, my heart goes out to the poor trusting folks who've sunken tens of thousands into their Mac Pro 7,1 hoping to be honored for years to come, only to inevitably find themselves in the same boat as G5 owners in 2005. I give them three years of support, tops.
Side note, I was surprised that in a very uncharacteristic move, Apple not only acknowledged the existence of Linux, but also showed AND interacted with an active distro (Debian 10) too. Which I thought was pretty funny because anyone who's looking between the lines and disapproves of macOS 11's changes were just inadvertently presented an alternative to use instead. Free advertising, hey.
Back to Big Sur, I thought the new interface (wallpaper especially) brought back echoes of early OS X, when desktop releases had open, flowing, abstract wallpapers as opposed to photographs, which iOS has already returned to for several years before now. And the
very slight return to skeumorphism of the existing flat icons (only after the departure of Jony Ive, no less) was an interesting turn of events to see as well.
Needless to say, I think Mojave and Catalina will eventually find themselves in a place very similar to where Tiger and Leopard are today. It will be very interesting to see not only where the future will take them, but most importantly how Apple's userbase will inevitably split up and react to this over time.
End of an era.
Inb4 the PowerPC Macs forum is banished to the Wasteland and Intel Macs takes over the communal brilliance thriving here as its successor.
