First, I was mostly thinking about historical corruption in the US, i.e. in the age of Robber Barons, which was really incredibly bad.

I agree there's probably less of the "money just unaccounted for" type of corruption in the US (though it does happen, especially in connection with wars and intelligence agencies), and certainly less petty bribes. But that may just be a symptom of more organized corruption, so that it isn't necessary to let to many lower instances have a cut. In short, there may be more legal ways to divert public trust to private gain, so that the petty sort is just pointlessly risky.