I have said for years that their salary should be tied to the median income in some way. Of course, I also think we should have term limits which would also eliminate the need for pensions. Let them have a 401K like the rest of us peons.
Yeah, we could try to vote the incumbents who have been there for 150 years out, but most people vote either their party straight or push the lever for the name they've heard of - year after year after year.