VW reliability is based to a certain extent on the past. Certainly the MKI and MKII era they were leagues ahead of the competition. You only have to look at how many MKII's are still toiling about on daily duty on this countries roads compared to similar aged fords, vauxhalls etc. My 2000 Polo (Touch wood) has been the most reliable and cheap to run car I have ever owned and that gets thrashed to within an inch of it's life and neglected badly, it's currently on 142K.
Modern cars in general are less reliable than older cars due to all the complicated technology. Ask any AA man and he'll tell you most stuff break down these days due to electronic/software issue, a small electrical issue on a modern car is a total ball ache to trace and repair. Add to this that most dealerships now only have 'fitters' and not actual mechanics, they struggle to resolve an issue that isn't a straight part replacement flagge dup by fault scan. Actual mechanical issues are much rarer. This applies to pretty much all brands. I think this is one of the reasons the costs of new cars are going up so much, they have to cover the future costs of warranty work.
Nick