Yes, there are ways to use social class to your advantage, even if just the ease to walk into a mansion and converse fluidly with the owner rather than feeling at unease. There are no ways to fully eliminate the effects of this, but MIT is at least not explicitly doing so.
And there is a lot more to admissions than numbers. Athletics do and should matter - robust health is positively correlated with future success. And essays, recommendations, etc. also matter. And I would think that MIT is not ashamed to say so.
When I knew the MIT admissions director many years ago, he said they had an X-Y chart with academics on one axis and other achievements/soft factors on the other. There was basically a minimum academic cutoff and above that cutoff you could basically tradeoff academics for other criteria.
And there is a lot more to admissions than numbers. Athletics do and should matter - robust health is positively correlated with future success. And essays, recommendations, etc. also matter. And I would think that MIT is not ashamed to say so.