When a person is purchasing a sports car, they do not go to the dealership and randomly test drive every single car on the lot until one feels right. They do not test drive a minivan, nor a SUV. They go directly to the sports cars. Why? Because they came to purchase a sports car! To test drive other vehicles would be a WASTE OF TIME.
Yet in the sales hiring process, we have all kinds of inefficiencies for God only knows what reason. I believe this is due to disorganization, lack of business acumen and power intoxication. What gets measured gets improved. Most sales hiring is done in a very ad hoc manner.