Meta learning can be useful, but I take your overall point. You can get lost in the weeds trying to figure out the "best" way to learn something. Autodidacts do have some up-front costs: they have to figure out how to best teach themselves a thing, which usually means researching and trying various pedagogical approaches to find something that might work for them.

Language learning, for example is a huge category. You can get completely mired trying to sort out "grammar translation" versus "direct method" or "comprehensible input" approaches, the pros and cons of spaced repetition vs extensive/intensive reading, phonology & minimal pairs, picking a textbook/grammar/dictionary -- it's a lot. I imagine there are some people who are broadly interested in language learning, and don't actually use that information to actually learn a language. It might be more fun to prepare to learn a language than to get into the challenging and less fun work of actually doing it. I see the parallels with "Gear Acquisition Syndrome".