I am sure that there are many servers out there who are in windows platform. Not to say unix is obsolete... u can have 2 unix server & 3-4 windows servers in a data centre. Just saying that windows are more in demand now. Tat's why they have certifications like MCSE.
In fact I think the new graduates are more into windows than linux which I think is bad. Linux is more robust & I do like to work on linux platform. More challenging :)