I have no idea what % of American households compost or live in places which offer municipal compost pickup but I imagine it's in the single digits. As evidenced by this article, compost is/can be an incredibly powerful agent of change: food production, habitat restoration, etc. However, most of us are putting organics into refuse streams where they're likely to be burned or buried in a way that's actually harmful because they release methane when they decompose under those conditions. It can be a bit gross and tedious to compost at home but there is a certain satisfaction which comes along with it.