Here is an interesting article that quickly summarizes why so many startups are born each day.
It's interesting that even though there has been considerably more scrutiny into the viability of startups since the late 90's, the severely decreased cost-to-entry has acted as a counterweight to that force. The result is that even without VC backing, companies are able to spring into existence. This is why we see startups flopping left and right and yet more and more keep coming. The ideas aren't necessarily better, the stakes are just smaller.