Influenced by big money, they no longer represent the people who elected them. The longer a person serves in Congress, the more attuned they are to remaining in Congress. It more than a job. Its a political career. It takes nearly a million dollars to successfully run for Congress.
Long timers know how to extract money from corporations and wealthy benefactors.
Those remaining in Congress the longest know their levels of power and authority will soar when they become committee chairmen. They then control enormous amounts of money and gain proportionally large favors from the companies they help regulate. The more money a committee controls, the more money special interests will contribute to their comfort and reelection campaigns. Extended careers in Congress do not ensure representative government. Rather, they ensure the seeking of political power and prestige and often frustrate the exercise of democratic principles.