I think PGs advice doesn't just apply to startups but to nearly everything in life. Learning (or as PG puts it, "Just Learn") is huge part of the equation if one wants to advance. You'll be surprise how this attitude is not very prevalent to the general population of adults.
Want to get earn more money? Just learn how.
Want that promotion? Just learn what you need to achieve.
Not an expert on a particular thing? Just learn from someone else.
In trouble and need help? Just learn where to find it.
Having said that, in my experience, I think another crucial step needs to tie in with learning is self-efficacy to make it worthwhile. Learning is one thing but if you don't have the belief to stick to it and act on it, learning will only get you so far.