Now the prices have gone up it's £1620 - £2225
depending on whether you have Dynaudio or a CD changer. Basically like any company they'll screw you for every penny they think they can get. And as plently of people buying a new car will specify sat nav, it's win-win for VW.
Plus of course TomTom, Garmin etc make literally millions of their products where VW probably sells a lot fewer so there's economies of scale. And VW get a car stereo company to make it, rather than a sat-nav company. And the VW unit is a DVD player and reads SD's and gets radio and will bluetooth your phone and knows how to interface with your reverse camera and tell you your arse is going to get heated and probably makes coffee too.
Personally, I think integrated sat nav is probably worth about £800, so I'd buy one on ebay and fit it myself. Or use last years road atlas and save myself another £800.