You’re right that legibility alone isn’t the whole story, but the reason I think Presties would still be advantaged in the many-slots-few-applicants story is that admissions officers also have a higher prior on Prestie quality. The impact of AOs’ favorable prior about Presties is, I think, well acknowledged; the impact of their more precise signals is not, which is why I think this post is onto something important.
You’re right that legibility alone isn’t the whole story, but the reason I think Presties would still be advantaged in the many-slots-few-applicants story is that admissions officers also have a higher prior on Prestie quality. The impact of AOs’ favorable prior about Presties is, I think, well acknowledged; the impact of their more precise signals is not, which is why I think this post is onto something important.