[skylark]

I think the biggest factor is actually time. Raw time.

In college I had 12+ hours/day I could spend doing anything I wanted, even accounting for classes, studying for midterms, etc. Multiply that across 4 years and you have 17,000 hours to spend all of your energy on. Some people do choose to go down that rabbit hole, and out of those people some will be successful.

Now that I've been working in tech for a few years, I feel lucky if I can find the mental energy to work on something for 4 hours/day outside of work.