I suppose it should've been obvious from the first two films being called A Fistful of Dollars and For A Few Dollars More and all 3 of them being colloquially labeled "the Dollars trilogy" but it is very funny how every single character in these movies is motivated by money to the exclusion of any other possible thing. There are no real good guys or bad guys, just people who's schemes to get their hands on some cash happen to fall in line with the law, and those whose schemes don't. Even then either side seems to play a similar amount of dirty, underhanded tricks to advance their own selfish goals.
I wonder how much of a subversion this was seen as in the 60s, since I've never really watched any of the John Wayne era cowboy flicks or serials. In some ways it feels like these satirize the western genre, where Blazing Saddles parodied it.