non-tech startup

Tom recently sent my this article on the best entrepreneurs under 25. On the eve of not qualifying for this age group, I've had a few thoughts:

1) Wow - quarter life crisis.
2) I'm impressed there are a few non-tech ventures on the list.

It maybe that I've been focused on the tech scene lately, or that there is no real community tied to other sorts of start-ups the same way there is with tech, but I was caught a bit off guard by it. It seems a lot of people spend a lot of time trying to come up with new technologies or more interesting combinations of old technologies, but I rarely hear about great new inventions - why is that?