From an interesting study which links entrepreneurship with not specializing during college:
Those who work for others can specialize in one skill, but entrepreneurs are limited by their weakest skill. Let there be two skills, x1 and x2. To make this concrete, albeit extreme, let income of specialists be given by
(1) income of specialists = max[x1, x2]
(2) income of entrepreneurs = λ min [x1, x2]
where λ is a market determined parameter that sets the price of entrepreneurial talent so as to equate supply and demand. This formulation captures the point that entrepreneurs must be good at a number of different skills to put a business together.