However, my initial thought was that MIT maybe has so many perfect scores it's useful at this point and not really a differentiating factor.
For example they can afford to have a perfect 1:1 ratio of men to women for a tech school and I don't think they lower their standards for that.
On the contrary, I went to a highly ranked engineering school of the same limitations (limited other genres of degrees) and it was 30% females overall roughly, but actually in general it was more like 6%-8% females in the actual engineering degrees.
I worked in the admissions office one summer and was hard pressed to find a B on any Q4 report cards which was one of my summer tasks to ensure no early admission students entirely flunked out. I got to see other things like scores and in general I have to say even at a lesser well ranked school, and reading the averages of every incoming class, my notion is not that there is a difference between the scores of smart hard working lower middle class vs the upper rich as much as there is an over emphasis on the exam as a whole.
I agree objective results are very important, and I don't have an answer for a way to calibrate across schools. I think AP exam scores are better indicators but not all schools have AB or IB classes, etc.
It is really at the end of the day like most things about your commitment and ability to get something done regardless of how tangential you think it is to your core goals or study. In real life it is the same way there are lots of silly things people have to do all the time to get where they want to be and the weeding out is those who don't stop trying vs those who find a comfortable spot and stay there and blame everyone else for not having the right priorities.
Regardless, I still fill like even amongst high ranking SAT scorers, students are good at acing them now. My theory though I'm not confident is true is that studying for them has been systemized so much that it is actually difficult for MIT to tell above a certain threshold of score what the bell curve is.
This is all with the exception we need to realize that the SAT is not objective or perfect (the top comment this one is in response to) it was only less than five yrs ago they pulled sailing terminology from the reading and vocabulary portions after having to admit children growing up in the Bronx indeed might not have casually sailed not had sailing related literature in their curriculums, making this a bit unreasonable even for "guessing from context".