TDI owners are not typical car buyers.
I know people that bought their TDI as prices were falling last year. And fuel prices will not stay low. The next crisis in the MiddleEast will begin pushing it back up. Then those that bought a quad cab tank, Yukon Denial, or Escalade will start whining and blaming politicians for their bad choice, again!
I know what you are saying, but there are still lots of people that buy microcars, small crossovers, and regular sedans (and yes, wagons) these days. I see lots of new Fiat 500, Nissan Jukes, Mini, Scion, and Chevy Spark, Sonic, Trax, or Ford Fiesta, Focus, C-Max etcetera with temporary paper licenses in the rear windows. Today's drivers are still buying small.
TDI drivers have experienced surprising torque, with fuel efficiency, in a tight and well mannered, easy to manuever, quiet vehicle. Many just won't accept a buy back, and will resist the "fix" unless administratively forced.
Based on what I am hearing in this thread, the people that are seriously considering the buyback are willing to take advantage of an offer "too good to turn down", which is a sensible position, but I predict that the buy back won't be that good. Many have high miles and ready to move on. If they do, they'll miss that torque!