You'd be wrong about how small the number is, and of those that do have a gaming card most will be budget cards.
Mine is not a budget card (nVidia GTX 660Ti)and I still get low frame rates at times because my FAMILY uses MY COCKPIT computer for:
iTunes
Weird crap that gets "accidentally" installed when I'm gone
4 different cameras downloading photos of crap that I don't care about
Windows Update keeps getting turned on
Free malware protection downloads because my wife thinks we need it and then goes into conflict
Sheesh! Having a family is tough