There are 10-15 blue bloods in the college game that offer the same opportunity to get great players and win on the stage that Bama is winning, but no one else is doing it.
So you can't just say Saban has the best players, he's the one that identifies them, gets them there, develops them, not to mention how hard it is to keep a bunch of highly recruited players happy, not wanting to transfer, and to play unselfishly. The other blue bloods have just as good or better of an opportunity to get the players that he does.
Miles has lost 15 games the last 5 years, Saban 7, that's a little bit of a gap. If Miles doesn't have Chavis, add about 5 more losses. Saban's also won 4 of the last 6 against Miles, with the 2 losses being pretty big upsets.