I once had the ambition to teach high school. I'm forever glad I did it, but that experience comprised the 2 most intense years of my life. My experiences in an Ivy League grad school and as professional engineer don't even come close.
Maybe his comment doesn't have the best wording, but it's true. I'd love to teach high school, but the way that teaching is structured and the compensation make me completely unwilling. My dream is to start a school simply where I can teach without the hamstringing of the modern education grinder, hopefully before my kid reaches high school.
I haven't met a single ambitious person in the US who dreams of teaching in a high school.
It's kind of sad that secondary ed isn't high-prestige in today's American culture, but it's not.