How would a graduate tax work in practice? Are you thinking % tax for the rest of their working lives, the same % for all graduates? If so that's incredibly unfair. Why should someone doing a humanities degree for 3 years with 6hrs contact time a week who lived at home, be paying back the same as a doctor/vet who studied for 7 years in student accommodation in London? Under the current system one would have debt of £52,875, the other £155,729, if they both ended up earning the same amount why should they both be taxed the same, for one to hugely subsidise the other?
I already think it's unfair they're charged the same tuition fees but at least they're only charged what they received.
What about people who do two and a half years and then drop out? They aren't graduates so do they not have to pay back anything at all under a graduate tax, not even their maintenance loans?
People moan about 'mickey mouse' degrees but there's never any agreement about exactly what they are, and what people don't like to admit is that those degrees, with fewer contact hours and often usually less expensive facilities, hugely subsidise the more 'scientific' degrees.
An eng lit or history degree = a few hours of lecturers a week, maybe the odd tutorial if they are lucky. Nowhere near enough books in the library so they usually have to buy their own texts. No practicals, no small group work, no expensive labs, no placements, no insurance....costs the uni, what, a tenth of a science type degree to provide but charged the same fees per year.
People stop doing "mickey mouse" degrees = universities will go bankrupt even faster.