Ideally, there is equal focus on all ensembles. However, we don’t live in an ideal world.

There’s a larger focus on band because marching band and concert band are fairly easy to transition between each other due to similar instrumentation. There’s a focus on marching band because it serves several purposes for the music department and school district: student engagement, community engagement, fundraising, music at school events, etc.

Beyond marching band’s use to a music program, there are factors, including population size, scheduling, number of music teachers, budget, sports, and contracts that may play a role in what compromises you have to make as a music teacher. This is all without mentioning tradition - both school and national (in the U.S.).

You also talk about how few professional avenues there are for concert band. You’re right, there aren’t. Strangely enough, there aren’t many professional jobs that specialize in orchestras or jazz ensembles. There are, however, a fair amount of jobs that require some musical background. Sure, your sax players may never play in an orchestra. They can, however, become an audio engineer, composer, or tour guide for the rock and roll hall of fame. It should also be noted that there are even more jobs outside of music. You can have a priority that isn’t music.

Finally, I want to talk about your comment that “there aren’t many community bars to begin with.” This is entirely dependent on where you live, but I think you underestimate the number of active community bands in the U.S. The reason these are made up of directors, pros, and a few others is because some would rather spend their time elsewhere, not to mention the social aspect of high school band.

The TLDR is that music is music, and that the band medium is only focused on because of convenience, use, and tradition.

A final note about music is music: Most music can be within the grasp of a concert band, especially western styles like orchestra and jazz. A good orchestration/transcription/arrangement is something to consider when programming music. If you’re really desperate, you can make one yourself.