[SomeStupidPoint]

Late reply, but I think there's a second harm to throwing out generalists in addition to what you outline:

Specialists aren't as good as generalists at integrating the work of specialists across domains (almost by definition). A lack of generalists can then lead to a situation where specialists are all making locally good moves, but the overall direction is negative -- something akin to Simpson's paradox (though, in the other direction).