It's very sad... I went to schools in Arlington that were quite good when I attended in the 70s and 80s. Our high school routinely ranked high on the academic achievement ratings (% of students going to college, average SAT score, etc.) _AND_ we routinely sent our high school football team to district and state competitions. Our soccer team was undefeated for years.
I've often thought it would be a good idea to separate academics from athletics. Have a "school district" that runs the schools in a building next to the football field run by the "athletic district." I think both are important, but you're right, North Texas public schools have fallen quite far from the academic standards they used to hold.