Well, I work in an industry dominated by what's called "new media". Radio, TV, entertainment, music, journalists, artists, actors, record label people, PR people, A&Rs, event promoters, investors, graphic designers. It'd be very hard for anyone to survive in any of these roles (and much more) without heavy social media usage, including location.
Having said that, I have friends on 4SQ who are software developers, chefs, teachers, optometrists and bodybuilders. So, you know. Depends on your social circles. I don't associate with anyone from high school except one person, I have no reason to. So they aren't even on my Facebook, let alone my 4SQ. Plus, most people don't really publish their checkins to FB, so if that's all your judging it on I'd say that's a pretty inaccurate judgment.
Like any social networks, they reflect the people you know. I happen to know lots of cool people. If the only people you know that use 4SQ are "unemployed kids from high school" than, with no diss/judgement, that says more about the people you know than anything else.