YS, the cost factor seem to be the “keep up with Joneses” phenomenon.
For those who go into chinuch, seminary is, of course, a prudent investment into future profession.
For people with more income, $30K/year is higher than BY but comparable/lower to college, and they can go to places where classes will be transferred for college credit.
Now for those in between, who are getting substantial discounts in schools and who plan to have grants/loans for college or do not plan to go there, the $30K is a shocking number.