Since we are exchanging anecdotal evidence :), every single one of my musician friends except just one person has moved to the mac in the last 10 years. The reason why that one person didn't is that he needs some Windows-specific software for work.
Ok, the situation in studios might be different (but I would curious to see actual numbers). In a live show you want reliable low latency audio (especially if you play VSTis on a keyboard or do any kind of live processing) and macOS is very good at this, better than Windows I would say. Dismissing this as "fashion" is a bit simplistic.
I'm a computer musician and audio programmer. Although I use Windows most of the time, I would be the first one to admit that the audio situation on Windows is a total mess. As Paul said, on macOS you have a single API and it just works (tm). On Windows, we needed an external company (Steinberg) to come up with a usable solution for low latency audio (ASIO).