At my last two workplaces Linux has been an alternative for those who wanted it, along with Mac (unlike Linux you have to ask for Mac, but you usually get it if you have a good reason or a couple of years experience it seems) and Windows (the standard).

Personally I have found Linux to be ready for (some) desktops (including mine and several friends) since around 2005 and I have even worked for a company that mandated Linux for everyone who couldn't document a need for Windows only software.