Read where I say that was a CLASS of 900, a senior class, not four years enrollment. There are five high schools of that size within 20 miles of my house and they are all doing a good job. Lakota East, Lakota West. Mason, Princeton and Fairfield. They all pay their teachers well and keep them a long time. They require contining education for their staff and most have post graduate degrees. But they can't require the dedication that I personally have observed.
I am not suggesting a cattle barn is a place for anyone.
What mega schools are you talking about? Where are they? Do you base this on personal experience? Do you have children or grandchildren who have experienced this first hand?
Here is a link to an article written in 2001 that suggests smaller schools are more effective for poor and minority students, but affluent students do better in larger schools.
http://www.wested.org/online_pubs/po-01-03.pdf
Both poor, minority, affluent and majority students are children, kids, important human beings, and they all have a right to the education that is best for them.