All well and good except..
Saw an American senator (I think) who was a former engineer, and on some committee who said that if such advances had been made that gave significantly better emissions, and/or performance, then it would be quite the discovery. The sort of thing that any responsible corporation would rush to patent.
So the question isn't "how come nobody except the dodgy engineers knew", but "how come VAG were so uninterested in their awesome technical advances that they somehow didn't patent it"?
Unless of course, they're lying....