Sometimes this is true. But lessons tend to be more memorable -- and thus more likely for us to internalize them -- when conveyed through an already-happened story that's remarkable.
Right -- the big question here is, What is the optimal amount of knowledge you should have about a problem / market? There are diminishing returns at some point.
And I don't see "diminishing returns" in knowledge as significant. There is always something else relevant to learn, maybe in another field but still relevant.