I don't think it's necessarily a privilege to have a childhood with a singular focus. Again, having your whole destiny picked for you leads to a kind of person who often does not lead themselves with any confidence. The trappings of success will be on them before they've ever faced a test from the engineering school of hard knocks. They'll try to lead right away (because they'll be sure they were picked to lead) but the smarter move would be to try following for a while.

I think the test is right: how long can you hold onto a single project so that you specialize more and more deeply? Every startup is an attempt to do exactly this, and most startups still fail.