[Jtsummers]

> A broad range of knowledge can scaffold together to reach new heights. Some knowledge that at once seemed useless can come back later (in light of other, newer knowledge) to become quite useful.

This is synthesis, and to feed it you have to (as you point out) have a broad range of knowledge. You don't need deep knowledge in every area, sometimes just knowing the surface is sufficient. But by having a wide enough knowledge base you can draw on those other areas when needed or make those random observations that reduce seemingly intractable problems in one domain to solved problems from another domain.