The entire question is confounding to me.
Are they accurate? They publish them so I’d assume so.
Are they made smaller due to vast amounts of unqualified applicants?? Define unqualified - whoever doesn’t get in?
Yes, lots apply who don’t meet statistical figures and in fact, some schools market to these people, perhaps to get them to apply to keep rates lower. Why else does U Chicago and WUSTL send app waivers late to people who never expressed interest?
If the only people applied met the 25th percentile statistically or above, yes acceptance rates would be higher - because they’d have less applications in the denominator. But many of those people - and even those at the 75th percentile, get rejected too.