Congressmen like all politicians, only care about getting reelected. Thats their most important mission in life. Once we start "kicking out" congressmen regardless of who they are replaced by, they will get the message and try to do what it takes to remain in office.
The mindset of reelecting incumbents has to go. In the free market we buy products that best suit our needs and do not buy brands/products that have failed us before. This keeps manufacturers on their feet as they all try to sell us the best product they can make. Democracy is the political equivalent of the free market.
You make a valid point and that is why it is so puzzling. Mr. & Mrs. America are some of the most sophisticated shoppers in the world. They will find the best bargains and generally get the best deals until it comes to politics when lethargy sets in and they just "reorder" out of habit.