The big ones all caught a wave and rode it, while these startups tried to create the wave. (Actually, that's not quite true - all these hardware startups were riding the wave of cheap Chinese components and free trade. It's just that it turned out the bottleneck for a hardware startup isn't manufacturing, it's customer acceptance. Apple rode the same wave with the iPhone/iPad, but they also had a well-established core competency of knowing exactly what the customer wants.)

There are still waves going on now, and there are probably some startups being founded right now that will get rich off of them. It's just that the waves probably aren't what VCs think they are.