If we look at Finals from the last 5 years of BOA S.A. and UIL 6A, only 3 Houston area schools show up.
2014 - BOA - TWHS
2014 - UIL - TWHS
2015 - BOA - TWHS
2016 - BOA - Cy-Falls, TWHS
2016 - UIL - TWHS, North Shore
2017 - BOA - TWHS
2018 - BOA - TWHS
2018 - UIL - TWHS
I think people recognize the pattern and are understandably dubious until it breaks.