Stop supporting Windows as well.

Open source developers are doing Microsoft a big favor when they support Windows and publish Windows builds and installers. It's a substantial effort, and apparently that effort isn't appreciated.

If all open source software dropped support for Windows, it wouldn't really affect the open source community that much. It would definitely cause headaches for Microsoft however.

It's not that easy.

I agree that supporting Windows helps its ecosystem.

But also open source software on Windows is an important gateway to the free world. When you are already used to Firefox, LibreOffice and VLC, you might as well switch to Linux painlessly, but if those didn't run on Windows, switching to Linux would require relearning everything.