That's essentially what I said - networking is part of quality; lifetime earnings are part of quality; all that added together is approximated by prestige, and there's little evidence that any of those metrics alone is better quality estimator than prestige alone.
I don't think I said what you said. I think quality is different from lifetime earnings, which is different from prestige/networking.
Quality in science can easily depress lifetime earnings (do the most brilliant scientists work in academia or for commercial interests? Where do they earn more), for example, and I already pointed out how prestige/networking can push down lifetime earnings because it offers a chance at power and power doesn't always come with as much money as one would have elsewise.
These are all in general correlated, much like IQ is correlated with success, health, non-criminality etc. but no one would say that IQ is a better metric to use than measures just of health or non-criminality.
There's a contrarian theory presented by Robin that people go to highly reputable schools, visit highly reputable hospitals, buy highly reputable brands etc. to affiliate with high status individuals and institutions.
But what would a person who completely didn't care about such affiliations do? Pretty much the same thing. Unless you know a lot about schools, hospitals, and everything else, you're better off simply following prestige as proxy for quality (in addition to price and all the other usual criteria). There's no denying that prestige is better indicator of quality than random chance - the question is - is it the best we can do?
It's possible to come up with alternative measures, which might correlate with quality too, like operation success rates for hospitals, graduation rates for schools etc. But if they really indicated quality that well, wouldn't they be simply included in institution's prestige, and lose their predictive status? The argument is highly analogous to one for efficient market hypothesis (or to some extent with Bayesian beauty contest with schools, as prestige might indicate quality of other students). Very often there are severe faults with alternative measures, like with operation success rates without correcting for patient demographics.
If you postulate that you have better indicator of quality than prestige, you need to do some explaining. Why is it not included in prestige already? I don't propose any magical thinking about prestige, but we shouldn't be as eager to throw it away completely as some seem to be.