There's probably still a fair few folks using 32-bit versions of Windows or Linux, despite the fact that a 64-bit version of Windows XP was released on October 25th, 2001. I doubt that many of those are gamers, but there's always that person who only plays certain games "and they run just fine so why should I change?"

NVIDIA is killing driver support or both newer GTX cards and Fermi models used on lower-end system. That will affect 32-bit versions of Windows 7, 8/8.1, 10, Linux and FreeBSD. That means it's probably time for an upgrade, unless you're playing games in a cave and not connected to the internet.