Morris, I thought that way when I studied the reforms. Bunch of middle class kids on a piss up (I was one), why should the poorest, who after all pay a larger share of income proportionally in tax (based on some sort of marginal utility) foot the bill?
But the answer was wrong because we were asking the wrong question. Not who should pay, or what, but is the system fit for purpose. Tuition fees were designed to massively expand the system at no extra cost to the government (ha), when what should have been happening was a huge expansion in vocational and technical education.
We now have a situation where the expansion means that it's a brave choice not to get a degree. And yet graduates saddled with debt are programmed to make choices in their own financial interest. An essential part of the Barr reforms (inbuilt designs to encourage people into science and engineering, or public service) fell by the wayside. People want to be high earners, and once they're high earners, they feel they deserve to be, because they paid for the their education! And the rest of us - with degrees that mean little - rot.
Disaster. Total failure of neo classical economics. I know, I was taught it at a leading economics department, by giant brained economists, and none of this occurred to them. Or at least, they didn't mention it 