Comment by yxhuvud

I feel this is missing the elephant in the room, which is that experts are not interchangeable. They have typically specialized in whatever they have spent lots on time doing, and so developers in different sectors develop a lot of different skills that are typically not very useful for developers in different sectors.

A result from that is that what may be trivial for people in one sector is hard for people in a different sector, and vice versa. Often people will not know enough about sectors different from the one they operate in to know what is hard or not in other sectors.