Yeah elementary teachers certainly work hard, but try teaching math, science, and social studies in high school ESOL with kids who don't speak English and are barely literate in their native languages and trying to get them to graduate. It's a challenge for sure.
I have done this. The odds are not good at all. You have to keep a perspective on it. Most of them are not going to graduate (at least not within 4 years). Your goal becomes helping them become functionally literate. Many times you just have to console yourself with the fact that you have given them more than they had. I always hoped that they would have a better understanding of the system when their own children became involved with it (which is quickly for many of them since I had pregnant students too). The first generation doesn't always "make it". BUT the schooling has not been wasted. We do a much better job of socializing people here in America than the Europeans do. We are avoiding lots of social problems by giving them whatever education we can. In fact, ESOL teacher may be the most important job in the high school (for society as a whole).
It is tough. You have to love the students and ignore a lot of what is flying around outside of your room.
And, if you want to make money, don't go into teaching at all.