It's a combination of things really:-
The American market is massive therefore more $$ for VW, so they treat their customers better.
American consumer rights is much stronger than ours.
American customer service is a LOT better than ours.
Americans are big on value for money.
VW is not a premium brand in America like it is here.
And quite frankly, because VW can get away with it here. Do you remember the appalling MK4 2.0 GTI? Yeah.....only Britain got that sh*tty engine put into the GTI. Everywhere else got the 1.8T.
As consumers, Brits don't stand up for ourselves. We are too easily bent over. We are the sort to moan to ourselves about the poor quality / service received in a restaurant rather than complain. We are too reserved and polite to kick up a fuss. Americans spit feathers at the slightest sign of poor service and woe betide any gas station that puts a gallon up a few cents.
Brits treat Audi / VW as premium and they charge us more, knowing we'll pay for it. In Germany, Audis & Golfs are just taxis. Here, they are status symbols.
Fair it is not, but it's always been that way unfortunately. VW of America is a bit different to Europe though. Pretty sure they are made over there and not to the same high standards as VW of Europe, although I could be wrong.
It's the same with Netflix. Netflix UK gets a load of ancient sh*t whereas Netflix America gets all the good stuff. They hide behind "international license laws" or some nonsense, but what ever!