OP, I actually agree with you that there should be more emphasis on academics, and that college admission testing should be improved and also made more difficult so that it’s a better test of knowledge and problem solving rather than a race to answer a bunch of easy questions as fast as possible without making careless mistakes. I also agree that colleges should get out of the business of professional sports and that sports involvement shouldn’t be treated as any more important than other activities.
But I think you are overly optimistic about the extent to which testing can identify talent and potential. And those do matter. You keep going on and on about pro sports and how they select their players, but you’ve ignored my suggestion to read about how sports are missing a large fraction of their talent pool because of the way they evaluate players. Read, for instance, the wikipedia article on relative age effect. https://en.wikipedia.org/wiki/Relative_age_effect which applies not just to sports but also to academics. If a simple thing like being a few months younger has such a noticeable effect, what about the larger challenges many young people face?
In my opinion the Universities should be looking for talent, both academic and in other, less measurable spheres, and in order to do this, you have to take a holistic approach or else you will miss many promising candidates.
I also think that there is a great benefit to diversity on campus and to a vibrant campus life. That experience is an important part of the education at an elite US college and if you cannot understand or value this, you don’t really belong at such schools because you wouldn’t benefit from it. If you base admissions solely on scores on very difficult tests, you will select for students who do little but study. That’s clear from the situation in China and other countries you cite. I also know well-educated immigrants from these countries who experienced this system themselves and would never subject their kids to it.
The experience in US grad schools is in fact that foreign students coming out of the type of systems you idolize are often not the best thinkers in terms of creativity and tend to struggle more with open-ended research such as is encountered at the frontiers of knowledge, though they certainly put US students to shame when it comes to solving clearly defined problems well.