I think it's a major problem across the board with new cars. Even fiestas are being fitted with wide low profile 17" tyres. That require ~£100 a corner tyres...
But it's the fashion of the moment. Put two cars next to eachother, one with 14" wheels and balloon tyres, the other with 17" wheels and low-profile tyres and you can guarantee which car will get people wanting it.
The fact that it utterly ruins the ride quality too seems lost on a lot of people.
Even me, with my sensible head, would take the car on 20" rims over the one on 17s. It just looks better.
Take my Jag for example, it's got 18s on it at the moment but several people have commented to me that I should get some 20s on there.