There can't possibly be Playstation fans, are there? Outside of Japan?
To possibly answer your question; Sony just makes black boxes and maybe some Gran Turismo or Crash Bandicoot bullshit once in a while. That isn't going to get you the kind of fans that Mario RPG or the Mother series will. Being a fan of Playstation is like being a fan of cardboard. Cardboard is really great, but nobody is a "fan" of it.
There definitely are, but they seem to be a different breed, partially for the reasons you stated.
I would also point out that playstation as a brand has nothing that has stuck around nearly as long as mario/zelda/metroid/star fox/etc.
but I don't think that it's necessarily a bad thing, I'd put some value on knowing when to stop.
but maybe that statement was less true before they showed off the new god of war, that would be the 4th platform to get an original game.
Really though, I'd say that it's less of a Playstation as a brand thing and more of a Playstation as a platform thing.
i.e. Nintendo fans are brand fans, which is why you see Nintendo brand products outside of Nintendo gaming products that are very successful. But for Playstation, you don't see nearly as much non gaming products, and the ones you do see are comparatively less successful.