About 15-20 years ago, a friend of mine who teaches communication at a university told me of a study that I think of every time I'm in a store and see vague sustainability messaging on a product. The study had two types of milk containers, each with the same milk from the same producer, but one had a standard label and cap, while the other had green-coloured labelling and a meaningless phrase along the lines of "for a better tomorrow". The milk in the green, meaningless labels outsold the other one, even without making any actual claims. I think years of greenwashing BS have made people not trust claims of sustainability or eco-friendliness.

Another issue is hyperbolic discounting. Even if a more sustainable option saves money of the long run, people are generally bad at factoring in future savings.