Musk is one of my hero's, but his first company was a web start up that help publisher's get news articles and other content online. He then built a money management system, which eventually became part of Paypal. These are hardly the world's important problems. But the exits from these wins allowed him to do what he is doing.
I think that's important to keep in mind if you want to belittle guys building Web 2.0 apps like Flipboard, reddit, ect.