It's a failure AND it is a consequence of certain driving habits (short trips and gentle low speed city driving).
In VW's infinite wisdom, they did not include a "regen in process" indication (which trucks typically have). They didn't want to put anything in the car that normal average everyday people wouldn't understand. So there is a DPF warning lamp but it only comes on when the soot loading is starting to go critical, and then it may or may not be able to recover.
Someone who does short trips at city-traffic speeds could very well interrupt a DPF regeneration after the end of their short trip, then the next time they drive the car and do the same short trip it tries an active regen again which gets interrupted again, and so on until it clogs because it is never able to regenerate. Fuel consumption is terrible in these situations because the controls are constantly trying to keep the exhaust temperature up.
People with diesel pickup trucks understand "If this indication comes on, keep on driving until it turns off", why couldn't people with cars understand that?
Diesels like long trips and working hard. Always have. These are no different, but city driving and short trips and gentle driving is even worse for them. Someone who drives 130 km/h for an hour every day will probably never need an active DPF regeneration. That's what these cars are designed for ... they don't like to be babied.