I use Windows on my primary computer to run Cubase, on my slave PC's to run Vienna Ensemble Pro, and a Mac to run Pro Tools for hosting picture. Many composers -- Hans Zimmer, for example -- run a very similar setup. Windows is quite common, especially in the film/game/TV scoring world.
macOS is an absolutely wonderful OS for audio work, and in a vacuum is my favorite OS (due in no small part to Core Audio/MIDI), but given the amount of power that we need and the lack of replaceable hard drives, PC's are pretty much always the better way to go nowadays if you're using a desktop. For laptops, though, I'd still nearly always recommend a MBP.
Source: I've worked in pro-audio for a long time, both independently and as an employee for one of the largest companies in the space.
Low-latency real-time audio streaming, for example, is a very common need, and the developers need to consider the same problems mentioned in the article.
I’ve anecdotally heard similar things about the video editing world - people would love to use Macs, but Apple took far too long to release the new Pro (and now it’s here, it’s out of reach for many “pro” users who don’t have unlimited budgets), so they had no choice but to move to Windows.
The whole “musicians use Apple”-thing is really not true — at least in my subjective sample size.
1. https://www.instagram.com/p/B1KlPQkgfIT/ 2. https://www.instagram.com/p/BpkqAq2n3c9/