But entrepreneurs are dreamers - you have an idea that you think is awesome, even if it doesn't currently fit in with a normal person's day-to-day behavior. But you're convinced that if it does catch on, even the people who were at first skeptical will come to love it, and the lives of millions of middle-class, tech-savvy individuals (because let's face it, this is typically the market you're going for) around the world will be a little bit better for your idea.

Yes, most of these people never actually build successful companies. But if you're just working on another straightforward B2B e-commerce platform marketed at the 10% of companies left who don't yet have a web presence, although you might have a greater chance of getting rich, you're not chasing the dream. And the people who see nothing wrong with this never become entrepreneurs, they just avoid the risk altogether and make a good living working at a big company.

It obviously doesn't happen in all cases (and I certainly don't mean to imply that there is nothing interesting and game-changing to be done in B2B businesses), but I think this could be part of the reason why entrepreneurs are always building things they hope people will pay for rather than things people already do pay for.