IMHO you are underestimating the leverage that Apple has given that macs are the tool of choice for most web developers. Apple is probably aware of this and this move looks like an anticipation.
IMHO you overestimate the use of macs as development machines, doubly so in parts of our industry that works on projects where high performance GPU APIs are actually needed (games, cad, simulations)
Macs used to be popular with developers but, this has basically changed IMHO. Perhaps they are popular with web designers still but, developers seem to be using Macs no more than the rest of the population to me now. It is Apple's complete lack of support for them that has brought this about IMHO and, I think it will be the end of Apple in the (very) long run (it will be the end of them as anything other than a phone manufacturer sooner and eventually completely I think).
>Macs used to be popular with developers but, this has basically changed IMHO.
Hedging almost-baseless assertions about verifiable facts by calling them opinions does little to hide the fact that you can't prove this and know you can't. IMHO, Macs are still very popular with developers, and the reason hasn't changed: a great GUI and a *nix command line. I personally would use Linux before Windows though because I hate both the Windows GUI and the Windows command line but I only hate the Linux GUI and could probably adjust to xmonad quickly and possibly even gain productivity. Granted I suppose I could use "Bash on Ubuntu on Windows" if I absolutely had to, however I think that name itself is an adequate synecdoche for my issues with the OS as a whole.
For what it's worth I feel pretty well supported as a Rust and Haskell developer in the Mac ecosystem, and Microsoft will have to do a lot better than give me bash to make me switch. It is a necessary but not sufficient condition for my computer usage ;)