Many.

I can think of a dozen people who got schnookered into 3+2 business/mba programs. They graduated with $150k in the hole (this was in 2000) and ended up in retail banking or working for the government in some civil service job that required 15 accounting credits.

The classic example of this phenomenon is art majors, who are basically unemployable in a “job” outside of teaching, and those job openings are usually cyclical.

Many means many things. It could be a few hundred annually and someone might still call that "many."

I'm dubious that many art majors wind up $300k in debt. Undergrad doesn't cost that much.

If your parents are wealthy enough to not qualify for need based aid, but not enough to be rich, your $50k tuition + $30k NYC living situation adds up quick.

Ok, so we've got $320k debt for NYU grads. They're at around 6.5k students graduating each year. I don't know what portion have "useless" majors paid entirely by debt. Let's say half. That's probably one of the worst offenders, but let's imagine there are around 10 more schools in a similar situation. Ok, 30k students out of around 4 million students graduating college each year in the US ... that's a tad less than 1%.

More than I thought, and enough to call "many", but perhaps still an acceptable level.