Why not have a reasonable, minimum threshold that selects a significant group of students that are at least capable of a decent level of success in school and r

Why not have a reasonable, minimum threshold that selects a significant group of students that are at least capable of a decent level of success in school and randomly select from that pool (eg lottery)? Stop all the nonsense of trying to write a perfect essay and have a perfect score on the admissions test. Just do good enough and enjoy being a kid and let a fair system randomly select from a qualified pool.