The discussion in Bill's journal (http://bitterlawngnome.livejournal.com/749607.html?style=mine) brings up the vital point that many communities require property owners to have turf lawns. That definitely puts lawns in an entirely different class than these other goods. (At least, if there's a residential community out there which bans jeans and requires residents to buy only name-brand groceries, I probably don't want to know about it.)

Fortunately the conservationists have made some changes to the law in Missouri so my father's been able to plant a native garden on one side of the house. But, as you say, legality is one thing, social pressure another. He's gotten one nasty anonymous note about it and he can tell that most of the other neighbours aren't happy, but they're too passive-aggressively Midwestern to say anything to his face, even after he's invited them to.