Have you spent any time in Houston and with Houston area college sports? It is somewhat like northeastern high school sports. Nobody ever has a truly large fan base, and small Elite schools often average almost as many fans per game as the largest public schools.
In most years, Rice will average between about 24 and 27K for football, and Houston will average between about 28 and 34K. For CFB, everybody in Houston is either a Longhorn or Aggie, except for those who are Bayou Bengals or Sooners or Razorbacks.
Texas Tech does not not have much of an alum presence in Houston, but TTU alums and fans are all over DFW.