Learning is work. It pays horribly, and you end up after a few years as a teacher, which is even more work and pays horribly.
If someone wants to live in great poverty in order to learn, that’s there business. If they expect to have a middle class standard of living, that’s being ridiculous. However the working conditions of learning full time, or teaching (and in Hebrew, “learn” and “teach” are just different binyanim of the same verb), are very good (no Shabbos hassles, no calendar hassle, no problem with treff lunches or seriously rude and immoral coworkers, etc.), which is probably why many people prefer poverty in a frum “job” (learning or teaching) to the riches of working for the goyim.