I know someone who spent $100,000 on their entire show (music, clinics, props, drill, costumes, choreo, etc) and then received a 2 at region. I also know people who do it all in house and have hardly anything besides kids and instruments on the field and make state consistently.
I think we have to stop coming up with excuses for why people succeed. It is an art form that is competitive, it would be easier if we all played the same music and marched the same drill but much more boring. Those that advance to the highest levels all sound fantastic so music is the top priority. Last I checked we still had more music judges than visual, but there is a visual element so that is included too.
Keep teaching and mentoring your students, focus on the small details, and encourage greatness in your program. They will come around over time, stop making excuses and make a great experience for your students.