Well, ND can't win a conference so that comparison isn't apples to apples. Winning a NY6 game is nice, but in this era it doesn't mean a whole lot because you have a slew of kids who sit those games out. Also, beating Utah, Memphis and Washington isn't the same as going up against Clemson/Bama. Riley's extremely close CFP game, was also the same team BK lost to in an extremely close game. It just so happened to be in the regular season.
If you're not going to count making the CFP or BCS title game, he hasn't accomplished much. Best win would be over Clemson in 2020. He's also beaten teams that have made a NY6 bowl, just not the actual game.