I'm a data point that proves the opposite of your claim. First, my ecodiesel truck ran flawlessly for the four years I owned it - I absolutely loved it. I had no desire to sell it, but I was approached by a dealer who made me an excellent cash offer for my truck, and the money I made for the truck now sits in the bank to make a downpayment on my ecodiesel Wrangler. He stated that they can't keep the ecodiesels in stock enough, so the used models have excellent resale value (at which point in time I probably should have tried negotiating a higher price on my truck, but I was signing the papers as we were discussing this )
Interesting... in my neck of the woods they can't give the ED away.