A. I'm currently serving as faculty at a graduate program, so I ostensibly have a say in the admissions process. This is my first year so I don't know how much time it takes, but I imagine a lot, even though the program is small. I don't know how in the world the academic staff can quickly filter from tens of thousands of applicants without some kind of broad benchmarks.

B. You act as if there is some absolute benchmark for "best able to succeed at [some subject]"...There is not. Sometimes the best engineers can come from people who hadn't initially aspired to be engineers and thus lack whatever credentials they could've built in their high school time. Sometimes character can be the factor in success, sometimes not.