A Ph.D. is great on fundamentals--it teaches you how to make something completely on your own--but it falls short on the practical stuff every entrepreneur has to master.

Being the best in the world holds little meaning if it is with respect to an infinitesimal niche of science that only you inhabit.

The culmination of the Ph.D. is supposed to be the creation of an independent and self-sufficient scientist who can continue to contribute to the scientific enterprise.

If you remain in science, it is almost certain that at some point in your career you will invent something--or be working on a team that invents something--that has potential commercial value.