For the first claim, 50 hours at 40 students would be 2000 hours. One year to complete the prerequisites for self teaching for those 40 students. Instead of 12 years full time lecturing, so that's 1/12th the cost.
I have volunteered at a school that allows students to become self-teachers and it is very effective. They follow the Sudbury model, and students entirely teach themselves everything from reading to mathematics. They graduate from college at higher rates than traditional school students, make more, and have very high levels of self reported happiness. It's a really cool model, I wish it was more common. The school I helped at had no teachers, only 3 adults for 120 young people. They could all come and go throughout the day as long as they signed in and out. It's been up and running for decades, so it's not just a flash in the pan.
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