they were great, yes, but they were not guys with established track records. They established their bona fides AT BYU.
Norm Chow, Ted Tollner, Mike Holmgren, Kragthorpe(s), Fred Whittingham, Dick Scovil (count Andy Reid if you want since he was a GA)-- these guys were not star coordinators until AFTER they were with us.
It was the fact that Lavell identified them as high potential guys and then gave them the freedom to become great that ultimately allowed them to become great. It isn't like BYU was out hiring the hottest up and coming coordinators everyone wanted. We've never done that.
As for the paying assistants part, that is arguably why we fell off heading from the 80s into the 1990s and toward the end of Lavell's career. We couldn't pay enough to keep our good assistants, they kept leaving, and eventually we couldn't keep replacing them with guys just as good and just as smart as they were. We launched the careers of many, but didn't get the long term benefits. That's actually pretty normal. A very underrated reason why Nick Saban has been so good for so long at 'Bama is that he kept a lot of his assistants a very long time. He has recently begun losing them at a pretty high clip and so I actually think that eventually they will start to slowly decline unless of course he is able to find similar caliber guys to replace them.