How ludacrous would this discussion have appeared in 1995 (the year in which I essentially live, perpetually) when Colorado, nebraska, Kansas and K-State all finished in the final AP Top 10. I know I make this point frequently, but I believe the lesson remains relevant.
I'll phrase it another way, less than 15 seasons ago (not so long) a full two-thirds of teams now in the Big XII North finished in the final top ten! Things change, and they'll change again.
The likely source of change? Well, Buffs04 inadvertantly hits the nail on the head when he breaks down OU and UT's records by COACH not by team. Concur that as long as Stoops and Brown remain with those teams, OU and UT will likely remain powerhouses (or not...there's always the "Fulmer Syndrome" and frankly Paterno has had ups and downs, too). But, coaches move on.
Also, good teams tend to flirt with NCAA sanctions. I'm not accusing OU/UT/TT/OSU of running dirty programs--I don't know a thing about it. I'm simply pointing out a possible impetus for change within the football landscape.
Finally, subtle changes to the broad CFB environment may provide unforseen impact. Baylor has historically recruited disproportionately well. What if 2008's momentum translates into success in the next several years? Maybe Sherman starts making waves in College Station. That could spell real trouble for Mack Brown's machine which is highly dependent on being top-dog for in-state recruits. You never know when some subtle recruiting rule change sinks an entire Coach's system. So many possibilities...
Things happen, the landscape changes. Be patient and let this great game chase it's own tail. It's part of the fun.
The North will rise again!