Well, not to be blunt, but going back a 100 years or so gives me records of senators openly complaining that some of their highly esteemed colleagues have been put in their seats by the railway companies or companies dependent on tariff walls.
And it kind of begs the question, why doesn't it ever change? It seems to me that at the end of the day the majority is not dissatisfied enough to do away with election spending, adding pork to bills, the super-pacs etc or to at least alter the elective process in any fundamental way.