A Generalist is good at many tasks, a Specialist only good at one. Demand for the output at each task fluctuates so it is good to have someone who can perform many tasks so “supply can match demand”. So, the Generalist is better for the firm than the Specialist.
But the Generalist’s life is hard – she is taking on a lot of risk. What will she be working on next? And she is the same rank as the specialist so she gets the same rewards. Better to coast on the tasks she likes least and work hard on one. More predictability and a better idea of what task to get better and better at performing.
So, generalists should disappear in the long run and the firm will just have specialists. Unless they can think of some way to reward generalists.