My point is, one's law school as a determining factor is just as ridiculous, problematic, and arbitrary as a "best proxy" as any of the above.
Logic FAIL. Students don't get randomly assigned to law schools. The best schools cherrypick the candidates that are most likely to be good lawyers in the future. The other schools are left with the rest. People are randomly born male, or black, or any of those other factors you mention. People don't randomly get into Yale. Your analogy is flawed.
I don't think that the best schools make the best lawyers. The students that enter the top schools are already better. The top schools just have to not screw them up. If Cooley and Yale were equal, Cooley would have to be so much better than Yale that they could take marginal undergraduate students with bad LSAT scores and other soft factors and make them as good at practicing law as people that have far surpassed them in academic and other achievement previously.
It's increasingly apparant that you're just trying to rationalize your own credentials. The funny thing is that I don't think all T3 or T4 students are destined to be horrible lawyers. It's pretty clear that you are though.