I know at least my company, employees who aren't devs or designers get a Windows laptop, unless they're considered a frequent traveler (i.e. sales role) in which case they get a MacBook Air. Designers get a MBP. Developers can choose between Linux and Mac, or Windows if you can justify it (we have some hardware engineers who actually need certain Windows-only software). We also have some new acquisition every few months and those companies get to keep their previous computers for a couple years before they have to get on the company approved device list.