Battle of the Swans: Why Is Nobody Talking About Solving Tough Problems?

As long as early foodchain players (YC etc) focus on the next AirBnB and DropBox, the world would get AirBnBs and DropBoxs. Nothing against that - they are wonderful profitable entities (and great efforts from the teams), but not the next Google.<p>Why Is Nobody Talking About Solving Tough, Interesting Problems?