I see that reflected in some of the computer ratings. Sagarin for example has only 2 Big 12 teams in the top 20, as opposed to 8 SEC. 5 Big Ten and 3 ACC. On the other end, there is one Big 12 team rated 69 or below(that's how many P4 teams there are now) same as the SEC, while the ACC has 5 and the Big 10 has 4.
There are a ton of Big 12 teams in the 20s and 30's, a lot good teams in there. The highs might not be as high as some other conferences, but they also avoid the shit teams...looking at you Purdue and Stanford. #116 and #106 respectively...only slightly better than Mercer @ #129.