Because universities are academic institutions, not track-and-field training facilities (or at least they are in countries that take education seriously, unlike the US). Who cares how boring it is?
Aside from the dedication of waking up to practice a sport every morning, think of how much time and discipline is it takes to balance being an amazing athlete with being a great student. They likely have all the mental fortitude and academic talent they need to succeed in college, no question, regardless of if they had a bad test day, or their pencil broke, or they had to use the bathroom and ran out of time, etc.
Someone with As and Bs, maybe a C, who did nothing else of note and managed to get a perfect test score one time doesn’t seem near as surefire a bet. If anything it shows you didn’t apply yourself.
Edit: you’re acting like performance on the test is completely arbitrary. Clearly, it should be designed to avoid this, and to actually test academic mastery. For example, someone planning to study physics should be asked to solve difficult physics and math problems. Someone planning to study history or literature should be asked to write long-form essays on those topics. And so on.
I feel like a lot of people in this thread are only familiar with the American system and thus assume that “standardized tests” all have to be like the SAT, i.e. answering a ton of relatively basic multiple-choice questions as quickly and accurately as possible. That is not the case.
Very few people will pick IIT or Beijing University if they are offered spot at Harvard.
Network - one of the best things you can do is put a bunch of intelligent, highly motivated people in one room and have them work on stuff together. Top tier universities are basically this. The actual education offered on top isn't that relevant as long as it's passable - these people will find a way to educate themselves
Signaling - having Hardvard on your resume is a global signal of your status and opens up so many more doors by simply having it listed by your name
Recognized by whom? I would certainly be more impressed if someone went to ENS Paris than Harvard.