I'm not sure the pay argument holds. For example, where I live, the average starting teacher salary is higher than the median overall salary. When you couple that with the fact they are on 4-day workweeks and get substantial time off (summers/holidays), the pro-rated pay is actually reasonably high for a starting salary. (Granted, I think it hits a ceiling relatively fast.) From talking to them, I suspect the driving force that make it hard to retain teachers is the lack of quality of life. I think it was Csikszentmihalyi who talks about the need for autonomy in one's career for it to be fulfilling, and the current system seems to limit that to an extreme. Just like u/lotsofpulp's comments about doctors, I think this means the job shifts much of the work from the purpose teachers chose the profession in the first place, and leads to burnout.