PC/Windows is the default developer machine by a large margin. That doesn't mean to say that the Mac isn't a good developer machine that some developers have chosen, but the PC still dominates. A PC can develop for Windows (duh!), Linux/BSD (using VMs or dual booting, even before WSL), Android. The only real "USP" for developing on Mac is if you're developing for MacOS or iOS and cross-platform tools like Xamerin won't cut the mustard (...but if you want to target both iOS and Android, a cross-platform framework would be preferable). Once you get away from one-man-band developers, the only people in a muti-platform development team who need access to Macs are the ones working on Mac/iPhone support.
As for Linux/BSD - yeah, back in 2006 it was great that MacOS was Unix, came with (then) GCC, PHP, Perl, etc. and you could run Apache, MySQL/PostgreSQL and all their friends - all on the same machine as Adobe CS etc... but, what I've found out down the line is that you're better off running Linux in a VM anyway, so you can match the target environment as close as possible and keep your MacOS file structure clean... not to mention that the way forward is containers, for which you need a Linux VM anyway. So once your development is VM based it really doesn't matter what host OS you're using.
MS are encouraging development on all fronts: PC (Visual Studio, VS Code, WSL), Mac (VS Code, "VS for Mac/ Xamerin") and online/in the cloud (VS, VS Code). I think the days of Windows vs Mac being the great battle is over and the big deal is Microsoft vs. Google vs. Amazon fighting over services (with Apple services other than maybe iTunes/Music a niche).