>It's much easier to make a story of relatable bumbleheads, especially if you yourself are somewhat uninteresting and never got much life experience.

I don't even think this is true, people just started claiming it. People love excellence. Characters don't need to be mediocre to be relatable. A character like Picard motivates us to be better than ourselves. We can still relate to him because he faces similar moral challenges, but shows us how we can rise above.

The "relatable" characters crowd are the same ones trying to make Superman less of a beacon of hope.