They have to raise money to stay in congress... it's a stupid system. Although it doesn't work that way here. What happens instead is that they make favours to big companies benefitting them or allowing them to earn a public contest for a big construction or whatever, and then when they get out of politics they are compensated with a nice job as consultant or ceo in a big company... not that everyone is like that. I refuse to believe that. But there are so many examples everywhere, frequently very well known by the public...