So 17 months in with corpses walking around and exposed to a couple of winters ..... wouldnt the bodies pretty much be falling apart at this time?

Second: Why haven't some enterprising souls just picked up something like an MRAP (or hey that Abrams from season 1), a few million rounds of 22 ammo and a dozen 10/22s and cleared out a few counties worth of land by hosting a rock concert / sniping competition?