Did BYU benefit from the efforts of both coaches? Absolutely....
Were there other coaches who could have made similar improvements? Sure....we will never know if they would have done as well as Mendenhall and Cleveland because they were not hired.
This narrative that BYU Football only survived because of Bronco and thus Bronco should be granted indefinite hero status I don't agree with. Could Reynolds have done a creditable job as Head Coach? Maybe....we will never know.
I'm glad that Bronco was hired when he was. I think the first 4 years when Bronco was using Crowton's recruits were special. I think the next 6 years were much less exciting and Bronco left the program with some gaping holes that are only now starting be be fixed. Bronco is no Lavell Edwards.