I don't think that the author of the post you're responding to is making any sort of normative claim.

> Sometimes the issue isn't time - it's money and access to schooling

I think the author is suggesting that if you have that kind of free time, then you either a) must be independently wealthy, or else that b) trading some of that free time for cash you can use to buy credit hours is a net positive because the guidance is worth it (again, assuming your goal is to learn math as opposed to eg obtain a uni degree).

I agree that's not necessarily a good assumption globally, but it's probably a decent assumption for almost everyone in the west, both in terms of self-learning capabilities and in terms of available funds.