Why are American university admissions so much more organized than American business admissions?
Easy answer: Application fees. And those who apply for free or for scholarships are essentially subsidized by someone else.
Hard answer: Universities weren't always organized. They used to be like businesses: highly patronage-driven. And they still are, due to legacy applicants.
But we're operating on a broken premise. Organized and polite recruiting does not correlate with meritocracy. Ask the Soviet Union or universities. Ask the huge megacorps who do reply to every job application.
Elite universities' organized legacy admissions undermine their claim that reading every application and responding to every student makes the process fair. I know corporate admissions worse, but my anecdotal impressions are the same. Patronage rules.
Making HR respond with rejections feels good, but it does not make the process more fair. Only attacking patronage makes recruiting fair. A lofty goal.
Honestly, the process isn't just cumbersome for the applier, it also causes trouble for other employers, because if you never receive a rejection letter from your first choice company, you're likely to move on to others, and if your first choice happens to get back to you with an offer after you've already contacted others, then you're wasting all the OTHER companies' time.
You say that one employer's neglect harms other employer's hiring. That's a good point, and it shows that organized applications, if applied across all firms, help everyone.
A single application system with a single deadline is kind of how universities admissions work. Maybe that's the best system we know. Can we have a system like universities admissions without the fees, is the real question?
Does a higher ratio necessarily imply more competitive? It could be that more unqualified applicants apply to more jobs than unqualified students apply to university. That would suggest that organization reduces the friction for matching the right employee to the right employer; but differences in ratio due to organization doesn't prove that the right employee is more likely to be matched to the right employer.
Why does this matter? If we take efficiency to mean reducing friction, then business will never inform applicants they were rejected. If we take efficiency to mean better candidates get better jobs more frequently, business will always inform applicants they were rejected.