Money and power are interchangeable, and that's what most ambitious people want. Of course, there are other benefits, like the joy of seeing something work, and the satisfaction of making a difference in the world. So most polite people will play up those benefits over the money/power angle.

Fame, hipness, insider knowledge? All either means to an end or cultural by-products. LA is run on power and money - studio execs are the most powerful, and basically run the entertainment biz, but they generally stay out of the limelight. DC runs on political power, plain and simple. Hipness is a by-product of having a very large concentration of young, single people in one place. You'll find brands of hip in every major city.

Ideas as Cambridge's main "industry" is also somewhat of a dubious distinction. Ideas are cheap. Talented people (i.e., the execution of ideas) is the bottleneck.