"Abraham Lincoln had a single-minded vision: Preserve the Union. Franklin Roosevelt didn’t really become great until he united America behind the cause of ending Fascism and Imperialism. John Kennedy asked us to put a man on the moon. Ronald Reagan was hell bent on winning the Cold War."

All of those examples are centered around war and/or homeland security and some of them don't have a lot to do with entrepreneurship. The beauty of the world we live in today is that we don't need a leader to supply us with a unified vision/direction; we have tons of companies simultaneously working very hard on innovating in a multitude of different areas.

There are a ton of problems to solve, so why focus on one?