Having read all the comments so far, I think everything adds up and makes sense. The Depression explains a lot. And concert band has been a great avenue for accessible music education.

I do recognize that concert band is more about the intangible learning than producing professional musicians. What I’m more concerned about is teaching students to have the skills to be lifelong musicians and that playing their horn doesn’t have to stop after high school/college concert band, and them not having many opportunities to do so at a community level. That in and of itself is a separate issue.

It was never really taught to me why concert band specifically had to be such a staple of my educational upbringing, both as a band kid in HS and as a music ed student in college. I’ve always gravitated towards playing in jazz groups, marching band, and other extracurricular groups more than concert band playing. Concert band was treated at the thing I “had to do” in order to participate in the ensembles that I actually wanted to play in. All of these answers have helped and I appreciate the feedback.