A lot of people are stuck on Windows or MacOS because of one killer app - Photoshop, a CAD/CAM package, a video or audio editor, or some proprietary bit of business software. Many of these applications have tens or hundreds of millions of dollars worth of dev time invested in them and it just isn't realistic to expect an open source alternative to compete.

I'm in that boat, but I don't especially mind. I run Windows because it allows me to run Fusion 360, but Windows Subsystem for Linux gives me a full Linux dev environment. A younger me would have got angry about it, but present me accepts that platform lock-in effects are very strong; fortunately for Linux, it dominates every new category of platform. I sincerely doubt that anyone will ever develop a new proprietary OS from scratch, because the business case for putting a pretty UI on Linux is overwhelming.