On the poetry point specifically, I really think writing degrees in general would be more successful if they were granted by trade schools (i.e. a focus on doing the thing, not a focus on academic scholarship about the thing).
To be fair, we also have compulsory schooling for that period as well, and it makes complete sense to use tax revenue to pay for something the same government is making you do.
Note that I don't oppose the use of tax revenue to fund voluntary education, and I personally benefited heavily from it. Its just that using the example of the government paying for something it made mandatory is not much of an argument in itself for having it pay for something that is voluntary.
Education and improving society floats all boats, just as the garbage man is dependent on people generating trash. Stocks fund companies that employ people who generate trash. That was a very narrow, short-sighted analysis of tax policy.
With loans, the govt both makes a return on the interest AND a lifetime increase in net tax revenues.
Value of a college education goes beyond salary, and ideally creates a better informed citizenry.
I believe people who support such things think as follows:
1. $15k a year tuition for 4 years is a great deal if it turns you into a banker or programmer with a $150,000 a year salary and a 40-year career. Indeed, it would be unjust for a garbage man's taxes to be paying for a stockbroker's education.
2. Majoring in poetry might not be such a clearly great decision, but if you're on the left politically, banning poetry is anti-intellectual; and if you're on the right market demand is its own justification.