It is meaningless to compare pilots' pay with high-earning jobs unless that is what you would otherwise be likely to be doing. I know a couple of ex-electricians who are now flying because the work was so tedious, and I for one would not want to be a consultant, and few people get the opportunity.
Most people who leave university start on well under £20k. A lot work in bars, shops or menial office jobs in which their degrees are meaningless for months or even years. With 30k of debt and no obvious advancement that is a rather more difficult prospect than surviving on even a turboprop FO's salary, usually significantly more than £20k starting, knowing that experience does count and the pay will rise. I have not checked lately, but a little over two years after starting my first public-transport job I came into the top 5% of earnings in the UK. The fact that in the UK that is still difficult to live on is down to the government.