Money certainly motivates politicians--but their pay as government employees is not what is influencing them. It's their donors! It's this system of legalized bribery we have. It's the offers to become a lobbyist, or have a cushy job in some firm of some industry that lobbied them while they were in office. That's part of what is called a "revolving door," where people from an industry will get into office, and those in office will go work in that industry. That's a real problem, not the pay these politicians get. Lowering their pay won't do much, maybe other than make for more craven politicians ready to take deals with lobbyists. They'll do more fundraising. You want to talk about excess? Look at executive pay. Look at corporate profits. They're higher than they've ever been.
Politicians are much derided and with good reason, but the real problem we have with them is the lobbying done to buy their votes. That's where we need some kind of reform. "Kicking the bums out" just puts new "bums" in, since they'll just be lobbied like those who came before them. Elections are a mostly superficial practice, where we replace one bought politician with another.