History is relative. Notre Dame is historically stable and better, but are you suggesting they are still a premier team these days? Since the 1970s, even?
Your point was that the Big XII "only" has Texas and Oklahoma?
Name any existing Big Ten team that has been relevant in the past ten years. Wisconsin and Ohio State are legitimate 9 or 10 win teams in most years, but after that . . . you have teams that run big numbers in conference and get trounced by the OOC or in bowl games. Ohio State is the only Big Ten team to play for the NC during the BCS era, if I recall.
As for the ACC, since Florida State started running rough in the early 2000s, they've relied on VA Tech in some years and who else? Some good teams (Top 25 ranking), but nobody is scared of playing the ACC.
All conferences except the SEC have one, possibly two elite teams in most years.