Because they need to maintain multiple huge servers and virtual machines with my favorite flavor of Linux, to make us doing the job very ineffectively. Because Linux does the job they need, it is needed, no escape, while windows is just for outlook and for creating issues.

I am paid enough that I really should not complain if companies waste money on the wrong tools for the job. Most of my salary pays to find solutions to problems that exist only because of windows. They have to waste a lot of money because the former accenture guy they hired as head of IT support (or whoever decides for the laptops) told them that windows is the only possible solution for big corporations. Good for them.

As said I am seriously thinking about starting my own start up, because my experience with corporate IT has been so miserable in all places I worked (outside academia, that has many defects, but at least they can manage a decent IT).