Look. I'm really not trying to get into an argument here that teachers are or aren't leshem shamayim. But the fact is that many come out way ahead financially while working much less hours and fewer days than in a job in the business world.
Plus many of these yeshivas and BYs don't require much in the qualifications department. So it can often be easier to get a Morah job than something else.
Really?!? A not-good Morah lasts maybe one year in today's day and age. Schools have a very hard time finding qualified Morahs to fill positions. Ask any principal. Low-supply, but still embarrassing pay.
They come out way ahead?!? You obviously don't understand the life of those in k'lei Kodesh. Get to know some of them better and get to know how well they are doing financially. Some are making it fine. Many, if not most, struggle horribly.