I see your point but also note that they have already done something similar with the M1. Pre-DMA and Epic lawsuit, I could potentially see them drop support for installing apps outside their app store. All they would really need is Adobe to agree and the rest would just have to follow, similar in some ways to the ARM transition. (With the notable difference being that one was free for developers aside from the cost of porting their software.) I don't expect that to happen now though.
I meant that they made developers make changes to their apps. The obvious difference is that this change will cost the developers more money. The point was that developers didn't simply abandon Apple when they switched to ARM. I guess this point may be obvious now but IIRC there was a lot of discussion around if Apple would be able to make developers make native ARM versions of their apps or if they would just abandon MacOS (although perhaps I am remembering wrong here). The point is that they made "every mac out there unusable" to an certain extent, (although obviously there was a Rosetta 2) and it didn't matter because developers followed Apple's direction and made them usable again by making ARM versions of their software.
Macs would become unusable because so much software doesn't come from the App Store. If they can get enough market penetration through other means first, that wouldn't be a problem. It would break all kinds of development processes, but Apple doesn't care about developers. They'd work out some kludge and do it anyway.
Why? Their whole "Pro" line is targeting developers. How many enterprises/startups would have to switch away from macs if they cannot be used by their devs any more?
They'd still be usable by devs. We'd get VS code on the App Store and some kind of iOS-style ability to run unsigned binaries on some limited number of computers with an Apple Developer subscription.
As for why Apple doesn't care about devs, I don't know, but they are not afraid of massive, breaking changes. Remember a few years ago when they permanently deleted the entire MacOS game back catalog by removing 32-bit support?
