I feel like 90% of the developers I know use Macs, even though a good chunk of the time they are just SSHing to Linux machines to do their work.
There are certainly groups where Macs are popular. Startups use a lot of Macs; when I go to a coworking space in Boulder mostly everyone has a Mac. They're super common in cafes as well.
But not everyone uses a Mac. Not everyone likes Macs (myself included).
[1] https://insights.stackoverflow.com/survey/2017#technology-pl...
All the servers that run the code I write are Linux machines, so I would say I develop 'for' the Linux platform. However, I use a mac laptop to type that code.
The vast majority of developers out there are using Windows. I would believe the majority of start-up engineers are using Macs, but the world of software development is probably 100x that of "start-up engineers."
Ahhh, anecdotes.
Also, you know ZERO developers who use Macs? That seems crazy, or you don't know many developers.