We have opportunities for state championships every year in Texas. It's called USBands and BoA. Football can't simply ignore UIL and have bowl games - they're 100% beholden to the playoff structure.
State-level Marching band is also much much more expensive than a state football team. Even factoring in five games to GET to the championships, you're talking two to three charter buses at most for the team to get there (plus whatever the band takes). Bands that make state typically need 3-5 charters or more, equipment drivers, and take a LOT more kids out of school (attendance dollars!) around the SMC.
Making marching band the 100% focus of our curriculum on an annual basis is financially irresponsible - to say nothing of pedagogically unsound. The reason we HAVE great concert bands is because we devote attention to them. Make everything 100% about marching band and you'll see a drop in participation in Honor Band as well as lowered performance levels in UIL C&SR.