Call it ecological consciousness, consumer disinterest, or lousy marketing: whatever the reason, the “disposable DVD” phenomenon is withering on the vine. The discs, which can be rented and viewed like a normal DVD for two days before they become unusable, are billed as an item of convenience for the movie renting public. But apparently, even American couch potatoes aren’t quite that lazy, because almost no one is renting the self-destructing discs.