Saban is a really, really, really good coach. If he had to play with average players then he would still be respectable but national championships are won by the players not the coaches.

Good coaches give players the chance to maximize their abilities. You can't get greatness from average players but you can get shit from great players with bad coaching.

The combination of Saban and his domineering, detailed coaching style and Bama's recruiting machine will give you a dynasty. Saban could do it elsewhere but not just anywhere.