Voters have to pay for bond issues as well as operating costs. In our state, those aren't voted on by the public but just approved by the school board. Not enough businesses to support all the high school sports fields in this area.
Football stadiums, equipment, trainers, uniforms are the biggest sports expenses here. Maybe 9 paid coaches and many volunteers, with dwindling participation. What was once an elite program, just isn't anymore. These upper middle class kids just don't want the concussion risk, so they all play soccer and golf, which could be easily done with clubs. Gate at football games is probably $3000 each for 6 or 7 games, so not enough to pay off a stadium that costs millions. Even if they share it with other sports, a stadium would never generate enough revenue to pay for itself. Then, we have the teaching positions just created for the football coaches to fill.
It's a thousand times worse at the college level, of course.