They probably figure that the "Kill 'em and take their stuff" is such a cliche at this point that they don't need to actually offer that as an option, since that's in the background as 'Story Hook 0' in every D&D adventure anyway.Hell... it's so cliche that Steve Jackson designed an entire series of games around the concept. LOL.
But the default story hook these days - "villagers are threatened by humanoids/undead/dragon, you must save them!" - is no more sophisticated. At least greed has the merit of being genuinely appealing to players. I'd guess many players take the 'save the village' hook just because they're supposed to, not because they feel any sense of obligation to a generic fantasy-world community.
I'd just like it if more adventures offered a nod to non-altruistic reasons for engaging with the setting and NPCs. I'll modify published adventures to suit my needs, but writers don't make it easy when they presume the PCs are going to take a particular altruistic and perilous course of action or the adventure 'plot' simply stalls. I think the key to supporting 'adventurers' rather than 'heroes' is to make locales interesting and attractive in themselves, rather than rely on specific social choices on the part of the PCs.