I think this is well covered by his first line:

> the main thing you need is free time and obsession (and money for your free time btw).

Free time (and money for your free time) is a privilege not everyone may have had. Also, access to computers which, don't forget, has only become ubiquitous this century, and sadly not always in the form that might encourage experimentation. Without getting too much into the Nature-Nurture debate, talent and obsession sadly won't go anywhere without the proper environment to cultivate it. You don't become Bellard/Knuth/Dijkstra with just a bunch of rocks[1] and a whole host of other concerns on top.

[1] https://xkcd.com/505/