Your joking, right? It is a hell of a lot easier to pay back 30k worth of debt with a good graduate job then it is to pay back 80K (sometimes more) worth of debt as a very poorly paid First Officer.
I take your point but it depends on your definition of poorly paid. Not every airline pays peanuts - I certainly don't consider myself poorly paid. It obviously depends on type and experience but within 18 months of starting as an F/O I was on more than my parents ever earned combined and I comfortably out-earn friends from home/uni who went into other careers, so an F/O wage, certainly if flying jets early in a career, compares favourably to the majority of graduate jobs.
It is very possible to service repayments of circa £1000 a month if you can quickly get into the RHS of a jet, unfreeze the ATPL (with associated payrise) and not have many other commitments.
If you have a mortgage and kids and/or can't get the first break on the other hand, life is more interesting.