A couple of things here, number one is that the program enabled a fair amount of people to purgase new light trucks with the voucher. Indeed it may have retired an older less efficient model, this wasn't exactly a Prius taking it's place.
Number two, it did take a rather large bite out of the used car inventories, this in turn raised the retail prices and due to a weak economy and some recent weather related events the prices are still artificially high. This hurts customers that because of their peronal finances must purchase used cars. Because of the mandatory destruction of the trade on vehicles, this also cascaded down to the wrecking yards (Pick n Pull, etc.) as well in reduced inventories. I'm surprised that dbroncs didn't champion this aspect of the program.
Third, I'm a little unsure about what the article meant about the recycling being a problem unless they were referring to the increased volume of cars being scrapped. The process is pretty well documented at every step and all of the materials are recycled according to existng laws.
Other than the temporary increase in sales I can see how one could make a case for less than positive results for the program.....
"An armed man is a citizen, an unarmed man is a subject"