"A more poignant campaign would revolve around convincing people not to buy certain unnecessary things at all, ever."
Which is not at odds with Buy Nothing Day and the associated movement. They're not just suggesting you delay purchases, but to buy from independent/local crafters or make your own gifts.
http://en.wikipedia.org/wiki/Buy_Nothing_Day
I haven't followed the philosophy to a T, but I've avoided the malls and chain stores fully, giving more personal gifts from Etsy sellers, local craft-meetups, handwritten cards, and baked gifts than ever this year. Supporting local/small businesses is always a good idea!