Increasing admission means they need more professors. Assuming an elite university has the best professors around, any addition ones are going to be of lesser q

Increasing admission means they need more professors. Assuming an elite university has the best professors around, any addition ones are going to be of lesser quality. Now the school is putting out worse students because their professors aren't as good as they used to be. Their quality of research drops because the students and professors suck and their reputation as an elite school goes away. Additionally, if you open the admissions more, you will effectively get students with lower grades. The more easy it is to get into a school, the less people think of it. You are catering to the lowest denominator.