Most people don't know about bitcoin. and the people who know, well they are for the vast majority sceptical, for now it's still incredibly a closed tiny world. Even if everyone talked about it for a while (the news, good magazines, etc) after the initial 'that's cool' people in the middle lost interest. I believe the main reason is that they perceive the entire thing like something dangerous somehow. I talked with a lot of firends that know bitcoins but are just too scared about trying and they don't have a good incentive (basically they don't need them): If you spend just a few hours on your laptop every day, you may see the entire thing like a distant and complicated world.