I am sure your post took a lot of energy, but it’s unfortunately rather inaccurate.
It’s certainly true that MIT has long been focused upon fields that require a high level of math, and certainly true that Harvard has long emphasized a Liberal Arts education.
And yet, prior to 2012, Harvard and MIT matriculated roughly the same number of the very top high school math contest winners. If you look back at the history of the Putnam awards, there are more considerably more winners from Harvard than from MIT.
This all changed around 2012, when MIT decided that it simply wanted these USAMO/IMO winners, made an active effort to recruit them, and pretty much got all of them since then. And after that, almost all of the Putnam winners have been from MIT. What you are seeing is the result of a conscious recruiting decision.
It’s important to understand that what is merely “a trick” for Terence Tao is likely something that mere mortals cannot understand even if they spent a lifetime trying to prepare for it. There is a reason why so many very capable students get a 0 on these higher level exams, and it’s not due to lack of effort.
It’s pretty clear that you don’t understand the process here, as it’s only the very first set of exams (AMC 10/12) that are multiple choice. The next level (AIME) is fill in the blank. Everything after that (and there are roughly four levels between AIME and IMO) is proofs based. Roughly 250 students each qualify for USAMO (plus roughly another 250 for USAJMO) to take a 9 hour exam over two days to solve six problems, and their solutions are graded manually because, being proofs, there are multiple ways to get at the correct answer. Each problem is scored from 0 to 7, and by far the most common score for each problem is 0.
Bringing this back to a running analogy the best I can, doing well on the AMC 10/12 is the equivalent of being a great sprinter, but in this case needing fast-twitch math brain cells to solve 25 problems in 75 minutes (3 minutes per problem). AIME is 15 problems in 3 hours (12 minutes per problem), so perhaps it is the 800 meters. USAMO as I mentioned above is 6 problems in 9 hours (90 minutes per problem), so perhaps it’s the 3200m.
Math research is the equivalent of a marathon runner, and it favors the slow-twitch math brain cells that can look at a problem for days or weeks and come up with creative solutions.
My son was pretty good at math competitions but is better at math research. But he also happens to know a few people that have been on the US IMO team over the years, and some of them happen to be outstanding at math research as well. There are certain people who can be the Bo Jacksons when it comes to math, excelling at both competitions and research, but the key is that they have an athleticism for math.