When I started the job, the little team I was on had a special deal that allowed them to use Linux; the rest of the company was on Windows. When I switched from Linux to Windows, it was partly due to outside pressure and partly due to a desire to help team members in India who did not have that special deal and were thus forced to use Windows. But a couple of years later, the special deal evaporated and everyone had to move to Windows...

I suspect that it is still common to be forced to use Windows at $BIGCO.