It doesn't come with Mint because it's a pain in the ass unless you hit the hardware lottery. My buddy's PC, which I also built, for some inexplicable reason runs Mint without any issues. Older hardware? Forget it. Although the issues seem to be X server, which may or may not be related to Mint itself. You'll have a hard time convincing me that OEMs want to pay the Windows tax and don't want to pre-install an OS that costs them nothing unless they have a legitimate concern about compatibility/support.