Excellent retrospective. I think what also elevates this film besides everything you mention here is its place in 1960s counterculture. It's very much a film about two men looking at society and deciding they want no part in it. One can understand, especially in the brilliantly ironic scene when Butch admits he's never killed a man, only to do so when lawfully defending another man's property. As he mutters bitterly afterwards: "Well, we've tried going straight. Now what?"