I think there's the base recruiting implicit to the school, or that's the heritage of the school, and there's the effect of the head coach and his staff. IMHO, Al Golden didn't dent Miami's recruiting, or if he did it was slightly below average. I think Randy Shannon out-recruited him, and Richt is definitely out-recruiting him.
Schnellenberger built a recruiting engine down there, and Johnson and Erickson kept it going. Johnson might have improved on what Schnellenberger did a little. Shannon picked up on that heritage and was in the same league. Miami has a few things going for it--the region, the commitment to athletics, (currently) Richt's recruiting talent, and the engine that Howard Schnellenberger built. While he was there, I think Golden was just a passenger on that train, rather than a conductor.