In my opinion I think it's just the free time to be able to put in the number of hours of deliberate practice. When you are younger you have far more time and flexibility to learn and experiment. In addition that time is spent on things that are seen to be new/better/modern and also come with a certain distain for doing things the way your predecessors did it. This mix gives the young person the flexibility of cutting corners and inventing/reinventing and by all appearance look 'smarter'.

I am now 30 with a wife 2 kids - I simply cannot put in the same number of hours of simply playing and practicing I did when I was 15-25. As much as I try to put in the hours, I need to face the fact I need to focus my time on them now. I also need to continue to earn a good living to give them everything I want for them (education, freedom). This means I am going to keep my 150k job doing things which may not be so innovative but I get to leave work at 5pm.

Whether that is a incorrect assumption I don't know, but from my perspective it feels true.