You said something wildly ignorant. Try learning a bit. Most STEM PHD's are "paid for" in service. The idea is you're training specialized academics, eventually they're going to become expert to the level that they can perform the kind of scholarship that will advance their mentor's scholastic program, at least that's the hope. The kind of technical training needed is best done hands on, which is why extensive laboratory experience is a must in many disciplines. In STEM fields it nearly always comes true, I can't say much for non-STEM fields. I take it back, the last PhD defense I sat in on (not a STEM discipline) the lady obviously was paying tuition. My question at the defense is always "what comes next". Usually it's a job or research position, but in this case my query was met with silence. Surprisingly, her research topic was quite topical.