A mate is a dentist. You try studying for 7 years, getting yourself tens of thousands of pounds into debt, then either work for someone who'll take 50% of your fees or put hundreds of thousands of your (or your bank's) money on the line to set up and staff a practice
How is this any different from any other highly skilled profession? Does your mate complain about the hard set of circumstances they have to muddle along with? Sounds like they're pulling your leg.
All skilled professionals have to invest a lot of time and money in building up their career. Then they often have to spend a significant amount of time making somebody else rich while they gain experience. Eventually they will find themselves in a position where they're earning a fortune, have a brand new car every year, a massive house, lots of holidays.
Oh hang on sorry, non-dentists may have to scratch that last sentence.