Because in a larger team (anywhere that is hiring, as opposed to two people in a garage) comparative advantage starts to kick in. Even if there are only two of

Because in a larger team (anywhere that is hiring, as opposed to two people in a garage) comparative advantage starts to kick in. Even if there are only two of us, and I am slight better at A while you are slightly better at B, the most efficient distribution of labour is that I do A and you do B, despite the fact that we can both do either. This gets more true the larger the team, because as the team (and the work) grows it is more likely that you have enough work to keep a specialist busy. A startup needs perhaps 1.5 coders and 0.5 business people, so two hybrids is more efficient than the specialist minimum of 2 coders and a business guy. But a larger business might need 5 coders and 2 business guys, so you are better off with 5 pure coders and 2 pure business guys because they will be more experienced in their specialty (and therefore probably better) than 7 hybrid types.