Hate to be that guy[1], but this does not refute the comment you're replying to.
1. There may be more than one important explanation.
2. Your data doesn't provide any information relevant to the evaluation of the hypothesis.
3. Many of the students at non-elite universities, however you define that term, are the ones that were not successful in their quest to go to an elite university. That's why the acceptance rate is so low. Those students would be the most likely to be affected by changes in the competitiveness of college admissions in the wake of the Great Recession, not the ones that were successful.
4. "Certainly the high pressure scholastic environment of certain high schools is not common." This is conjecture. It does not seem plausible that it is "not common".
1. There may be more than one important explanation.
2. Your data doesn't provide any information relevant to the evaluation of the hypothesis.
3. Many of the students at non-elite universities, however you define that term, are the ones that were not successful in their quest to go to an elite university. That's why the acceptance rate is so low. Those students would be the most likely to be affected by changes in the competitiveness of college admissions in the wake of the Great Recession, not the ones that were successful.
4. "Certainly the high pressure scholastic environment of certain high schools is not common." This is conjecture. It does not seem plausible that it is "not common".
[1] Not really, but I'm supposed to say that.