A&M played in two conference championship games in the history of the Big 12. One was before either Mack Brown or Bob Stoops were hired. The other was Mack's first year, OU's last pre-Stoops year. Once Oklahoma and Texas got their programs back to their normal levels, it went like this for A&M:
1999: three way tie for third, one game back (defeated us head to head and still finished a game back of us)
2000: third, three games back
2001: tied third, three games back
2002: fifth
2003: fifth
2004: tied for third, three games back
2005: fourth
2006: third, two games back
2007: three way tie for third, two games back
2008: tied for fifth (last)
2009: fifth
2010: three way tie for first, did not have tiebreaker
2011: tied for sixth (with us)
So from the time Bob Stoops was hired and Texas and OU started winning on their historically expected levels, A&M never even seriously contended for the Big 12 South title. When our program cratered in 2010, they shared their only division title post-98.
In the SEC, they've gone this:
2012: tied for second, one game back of a team they upset head to head
2013: fourth
2014: sixth
2015: tied for fifth
2016: fourth
2017: tied for fourth
2018: tied for second, three games back
That is during peak Alabama, another program that's simply capable of much higher output than A&M. And the rest of the SEC hasn't been killer the rest of the time A&M's been there, either-- LSU has been good but not as strong as they were from 2003-2011. Auburn's up and down, Florida's on their third coach since A&M joined the conference, Georgia has put together three fine seasons but A&M hasn't even played them. Ole Miss and Miss State exceeded historical performance, but I don't think many Aggies would see either of those programs as legit obstacles. Arkansas and Tennessee have been as bad the past 5-8 years as at any time in their histories.
In other words, not only is A&M not contending in the SEC, they're not contending during a time when there's only one blueblood (Alabama) to surmount. If LSU gets its act together, if Auburn gets consistent, and if Florida and Tennessee re-establish themselves and compete with Georgia, A&M will fall further from contending for conference and even division titles.
I don't know how else to explain this to people who keep credulously referring to A&M as a sleeping giant (Stewie Mandel). They're not. They're Mississippi State in a more talented and therefore more hotly contested recruiting area. Winning 8 games and finishing two games back in their division is a good year for them. A breakthrough is sharing a division title and losing the tiebreaker.