I guess we are talking about two different things, both of them useful. One is excellence in a given field, where the success could be described like “you got a Nobel price, bunch of stuff is named after you, and kids learn your name at high school”. Other is keeping all aspects of your life in good shape, where the success could be described like “you lived until age 100, fit and mostly healthy, with a ton of money, surrounded by a harem of girlfriends”. In other words, it can refer to being at top 0.0001 % of one thing, or at top 1-10 % at many things that matter personally.
One can be successful at both (I am thinking about Richard Feynman now), but it is also possible to excel at something while your life sucks otherwise, or to live a great life that leaves no impact on history.
My advice was specifically meant for the latter (the general goodness of personal life). I agree that achieving extraordinary results at one thing requires spending extraordinary amounts of time and attention on it. And you probably need to put emphasis on different rationality techniques; I assume that everyday life would benefit greatly from “spend 5 minutes actually thinking about it” (especially when it is a thing you habitually avoid thinking about), while scientists may benefit relatively more from recognizing “teachers’ passwords” and “mysterious answers”.
How much could a leading mathematician gain by being more meta, for example?
If you are leading, then what you are already doing works fine, and you don’t need my advice. But in general, according to some rumors, category theory is the part of mathematics where you go more meta than usual. I am not going to pretend having any actual knowledge in this area, though.
In physics, I believe it is sometimes fruitful (or at least it was, a few decades ago) to think about “the nature of the physical law”. Like, instead of just trying to find a law that would explain the experimental results, looking at the already known laws, asking what they have in common, and using these parts as building blocks of the area you research. I am not an expert here, either.