too new
The problem is that the car is really still too new. It's only been out for 1 year now and it is rather desirable, which is going to keep the 2nd hand prices higher for a while to come.
That said, Volvo do tend to keep higher than average resale prices. If I look at Volvo's predictions, they expect the car to lose 15k of the 27k purchase price over the next 4 years. 44% value after 4 years is good. Only time will tell.