[adam the great]

Competitive salaries with other similarly-qualified professionals in private industry. Without competitive salaries, you're not attracting the best people to the profession. The best people are going places where they can make more money.

There's plenty of qualified individuals who are working in industry, that would make wonderful teachers, and likely even have the desire to do so, but when you look at the pay cut they'd be taking, they would be setting themselves back YEARS in life financially.

This exactly. I remember nearing the end of high school when its time to choose where to go and what to study having two conflicting desires. I was really good at math and enjoyed everything to do with it and often had my math teachers ask if I was going to become a math teacher after college. And after doing robotics for 4 years I also was considering going for Mechanical Engineering. However being realistic and doing the math behind average salaries and such between the two it definitely influenced me to chose to do Engineering. Even now if an opportunity ever arose for me to change over to teaching STEM or Math of some sort at a rate that is comparable to what engineering prospects are I'd consider it all the way. But all those points you listed are all real reasons why students are staying away.