Ecosystem lock doesn't really matter to developers. DirectX is an ecosystem lock.
Let me rephrase that, locking into a eco system where no serious money is to be made. You'll find ecosystems everywhere, including Nvidia with Cuda and all their tools. And for most people that is ok, because there is no alternative. The difference is, everyone is using it. If I could jump off the Nvidia train, I'd happily do it. But where exactly do I go if I need 500 GPUs in a Cluster? Not to speak of the software side of things.
Uhhhh is this a joke? UI code is supposed to go on the main thread. Even on macOS. Even if what you mean is "UI code not on the main thread" that's pretty trivially fixable.
UI code off the main thread = not on the main thread. So many people still do it. It's one of the reasons I let my students fail whenever anyone is submitting such code. It's just not acceptable.
Looks like your holdup is PyRep. It's a macOS issue that has nothing to do with ARM or "UI code off the main thread." I'd be happy to send you my rates but I'm guessing you aren't serious.
Of course I'm not serious, because it's not worth to fix it. I could fix it myself, but it's not worth the time. If you fix this one thing, then you have to fix the next one and the next and so on. And before you look at it, you'll have to maintain 1000 different tools that someone else screwed up. Who's paying for that in the end? It's much cheaper to just buy additional hardware und run it there, money is usually never an issue for getting immediate tools that just work vs. maintaining multiple projects.
Edit 2: Yeah, I see what they're doing. It's absolutely fixable, I've fixed this sort of thing before in other renderers. They likely just don't care.
They don't. Few people do, you'll find these things pretty much everywhere in the research world.
I've literally never seen this problem, and I've ported stuff to ARM that's literally decades old without having to re-write it from scratch.
So have I and I've run into problems that were so time consuming that it's just not feasible doing it. I've found that problems usually are caused by those who don't care much and cause these problems. Look at Path of Exile, it won't run on M1, neither native nor with Rosetta. They're using 3rd party libs making use of AVX instructions that Rosetta can't translate. They only have three options, do nothing, wait for the 3rd party to update their libs or throw the 3rd party stuff out and replace it with their own stuff.
In case of WoW for the M1, I'd guess they had things done to spec for macOS on x86 and that's why they simply "flipped a switch".