Let me clarify. Because of the MQB, the engineering costs are more evenly shared and the engineering is better relative to their costs. Like bigger brakes on base models, or better base engines, or the same drag coefficient despite the bigger interior dimensions. More serviceability like heater cores that can be replaced without removing the dashboard. Filters, fluids, and other consumables used by MQB vehicles, lowering the overall cost to service. Less part numbers in inventory, further lowering manufacturing, logistics, and engineering costs.
Yes, the Mk6 is not as "good" if you look only at what makes a German car "German". Like trunk hinges that intrude into the trunk space instead of a multi-link hinge hidden in the margins. Thinner metals in the body, no soft-touch dash, no analog fuel or temperature gauge, etc. Of course there are things you will notice. With the Mk4 and Mk5, VW tried to compete in the same space as the C class and 3 series, at the price point of an Altima or Civic... the result was horrible reliability, components built to meet a price point instead of a quality point. I think the Mk6's overall quality is worlds ahead of even the Mk5.
Point is, VW had to compete globally and they were able to deliver a highly competitive car in the industry while dramatically reducing costs. To the vast majority of people, the car is better in every way. To enthusiasts, we see them as cheapened out, but having owned 30+ VW products, I don't believe it was to the detriment of the generation. Basically, in a global market, it's a comparatively better car when you look at the big picture. Don't mistake features and design language with quality is all I'm trying to say.