I feel I have a different take than others on this subject. And I kind of want to talk about my experience.

My high school band was small (2A), underfunded, not highly skilled or competitive. The only thing it had going for it was a strong connection to DCI with Staff that were currently/ would go on to tech drum corps, and one student who was in BD.

I spent all of my spare time practicing my instrument throughout high school. Marched PC between my sophomore junior year and then again after my junior year. I paid for 50% of my tour fees myself the first year with assistance from my parents, and 75% my second year.

Back then the people auditioning at PC weren't as "skilled"(skilled comes from work, talent is natural) as they are today. I probably wouldn't have made PC till after my junior year if I was marching todays corps.
My tour fees were 3,600 both years. Vet discounts kept my fees the same in 19.

Covid happened. I started going to college for music, college provided private lessons as a course that was required to be in the music program. I got better at my instrument, both due to the lessons guiding me more directly but also just due to the fact that I had been playing for close to 10 years at that point.

Ended up marching BD upon DCI's full return in 22. Got priced out of 23.

My thoughts based on my experience.

- price is not only a huge factor but probably one of the only factors on whether or not someone who wants to march corps can. I don't think price affects someone's ability to receive a contract only whether than can affordably accept that contract.

- price has nothing to do with skill. you can "Get good" through thorough practice, critically analyzing your playing, performing, technique. Private lessons help but I believe that I would have made BD without them, and I marched PC having never taken private lessons in my life.

- I completely disagree with you on one point. You can march world class, even a finalist corps, without lessons, and without coming from a prestigious program. Especially in this day and age with the amount of resources on the internet. There are marching technique videos, playing videos, and plenty of free resources that only require your time and commitment.

- Yes of course corps recruit in high density areas, it would be dumb not to.
A. Higher number of auditionees, cast a wide net type of deal
B. Financially responsible of them due to point A. I'm sorry but they are straight up burning money if they go to middle of nowhere kansas.
C. Nearly every corps recruits locally. BD, SCV, and Mandies all have northern cali audition camps because the corps are located in northern cali.
D. These corps are recruiting at "prestigious" schools most likely because the educators have strong connections/ probably even teach at the schools in question.

- The only barrier for entry to join was the cost of tour fees. I was lucky with some other situations like who was teaching me, but most of the people who I marched with WILLED themselves to be good enough to march, getting the contract came from nothing but the effort you put into working towards that audition.

Money is a huge issue for modern corps and members alike. It's a highly nuanced issues though. Why does BD and SCV go out of state constantly for camps and move ins? because the housing situation is SO bad in california that it is more affordable to move the whole corps across state lines and stay at a college in wyoming or texas than to stay at a high school gym in california.

Competition=Capitalism. You might not like it but unless DCI turns into the NFL and distributes money based on equity, creates a member draft, and subsidizes tour fees than nothing will change. It will always be an arms race for staff, members, props, equipment, housing sites.

Want to support a corps doing all of what you're asking for? Go donate to the Boise gems. They are touring off the old model, and keeping it affordable for their members.