Driving them off Mac would be a gigantic mistake that over time would lead to the fading of the whole Apple ecosystem.
I think the mistake already happened, you can see fewer and fewer macOS only software and there is very little in the way of novelty/exclusivity (both iOS/macOS). Devs are now more and platform stuff more and more (mostly web technologies because it makes for good UI even though performance is not the best, it doesn't matter with today's powerful machines.
I'll add that one key point that Apple was better on is becoming very moot: software optimisation (performance and UI) matters a lot less in today's cheap powerful computing. Apple is supposedly selling top of the line hardware but skimping every way possible so in the end, when price matched, competitive hardware does not do worse no matter how bad the softwares are optimized on concurrent platform.
Then the usage of the platform will end for many users & developers. One could still live a quite long time on the older systems to ease the transition out.
I do create macOS binaries, although they mostly are just a byproduct if targeting it is trivial. Of course I do not sign any of them, to me that is more or less a scam comparable to ransomware.
This way I support Windows 2000 or newer, MacOS 10.6+, up to 15 years old Linux distributions with the same small binary for each platform, I did an extra mile in supporting WebAssembly target so it's easy to compile the applications to the web. This also allows to create applications for smartphones without the need for approval and having to follow any weird arbitrary rules.
Why support such old versions? Real world users are often stuck with old versions for various reasons, it's a minority of users but they can be the most important ones. And technically because the difference between these old systems and new systems is not that big. Often it just means to use some older API or do a few extra steps. It's all hidden in code that handles multiplatform stuff so it's not in the way. It doesn't add bloat either.
Well yeah because they are very sensibly doing it extremely slowly. Microsoft is doing the same thing; they're just a fair bit behind Apple.