This is a great question. In my opinion, the problem and the solution rely on the voter. When the politician doesn't meet his promises or the goals expected by the voters, then the voters shouldn't reelect him. If this theme continues election after election, the politicians would get the idea that they must serve the people.
There is no reason for politicians to Nest in office until they die, or do something criminal and get out of office. The idea that these nested politicians are experienced, doesn't float any better than the Titanic after the iceberg. The end result today is that congress and the president for the last several decades had pushed the country into decline, a decline that continues today.
The politicians are either the problem or the solution. If things don't get better during their term, then released them back into the wild.
The problem is the people, the political parties have trained them like Pavlov's dogs. The dinner bell has been replaced by the election bell, and off they go to check their Row on the ballot.
We have many generations of these voters, and until they can use intelligence over conditioning the country cannot change for the better.