A lot of these kids are not "Texans" - but rather came here from rust belt migration, Katrina refugees, etc.
"The grass is greener" effect is very real when coaches from other states/programs tell how much their programs are better - real or not...
The intense heat/humidity of College Station is a drawback for many.
Many kids do not have the IQ to attend A&M, and if they do Stanford, Rice, the Ivy's, etc., are all waiting...
For those who are not good students, bordering states offer an easier path - especially with more "easy courses" than A&M to offer prospective athletes.
A&M has a distinct conservative culture with many traditions from a military background. This is a turnoff for many kids who prefer to be "progressive" in their ideology. Not everyone is cut out to conform and be "an Aggie".
Let's face it - Bryan-College Station is great for families and raising kids - but for single college age kids, there really isn't a whole lot to do... and city life on weekends to Houston, San Antonio, Austin and Dallas-Fort Worth beckon every weekend.
Etcetera...