OS X is a dream to develop for. It really is amazing.
Windows, is honestly, not terrible. I don't know anything about C# or Winforms or whatever modern Windows GUI apps are created in, I used Win32 API and MFC. They may have been a little kludgey, but they got the job done. Lots of documentation and code out there, like 20 times as much for the Mac.
Now, Linux... I've tried. Haven't gotten far. Both Qt and GTK.
Anyway, it's obvious why everything is written in Electron and friends. People are familiar with it. Everyone's a web developer. It's cross-platform. It's a big deal to learn another environment. Why wouldn't you want to be able to run on Windows, web (phones/tablets), Linux...?