That portion of labor is lacking, because it is not rewarded. It is not searched for during interview, it is not valued in mythology (what we consider cool when on blogs and forums) and lastly is not rewarded by employers at work. Notably, actually predictably matching timeframe is devalued where people who end up pulin overnights due to bad planing, lack of comunication/negotiation are seen as heroes and rewarded.

Why would culture developed skills that make you rewarded less?

The ability to teach juniors is not searched for nor rewarded either, where social skills are even sometimes treated as something that makes you less good as programmer.