The reasons have already been covered here but mainly, Miami cannot give out non-commitable, early offers to local kids like candy because if those kids don't pan out, Rich and the staff become "bad guys" in the local community when they rescind on their offers. Somehow, Saban gets a pass on this sort of thing because "well, that's Bama" but it's bull**** that the local coaches and money grabbers...err "handlers" hold the Miami staff to a totally different set of standards.
Here's another point. Golden offered every 9th and 10th grader in the tri county area and often got commits from kids two or three years early. Then we all watched those kids use their Miami offers to leverage offers from schools they really wanted to go to and old fat Albert was left holding his itty bitty crank come signing day.
You're damned if you do. you're damned if you don't.