Whizbang Dustyboots
Gnometown Hero
Because it's a brand name with a 40 year history. Pathfinder was introduced at a time when new RPG brands were getting little notice by the public -- I don't recall even Traveller, Runequest or Call of Cthulhu breaking out into the public consciousness back in the day -- and unless you go hunting for information about RPGs (or, now, sites about MMOs, although it's barely a blip there), you're not going to hear about it.(So, for edit 1, I wonder why D&D is so much higher? MMO?)
Popular entertainment and news about it have both splintered into a million different directions since the 1970s. It's possible to live your whole life without being aware of who the "biggest" names in pop music are, and listen to a whole bunch of vibrant music in an entirely different genre that the "pop music" folks won't ever have heard of. (The fact that both of your musical tastes will actually sound pretty similar to a third party just underscores the level of fragmentation.)