Could be the African Meltdown talking!
Anyway, I have a little more faith in politicians than you do. I see people in politics for their own personal power (and to aid their friends), and I see people in politics who are fed up with the people in it for their own personal power. I don't use quite as broad a brush as you do, but then we also have two different feelings about living in places where you live side by side with millions of other people, aka cities!
I think SOME people get into politics for the right reason. They usually do well in the smaller local arenas. Then they get into bigger politics where the machine is more important than anything else. Furthering the power of the machine. If you get into bigger politics and don't play by big party politic rules, you don't last long (they won't back you the same, you're a renegade to them) and if by some chance you do stay around for a while, you likely get relegated to the most undesirable committees and sub-committees. There are pecking orders to get into the powerful ones. And to get into those you have to prove you put the machine before the people. So those that have the best of intentions rarely make it far Shed. They do well locally. Unfortunately they never pan out. Both sides work to ensure nothing can disrupt the machine.
Then you have people that get into politics for the wrong reasons. The Clintons, the Bush's, Pelosi, Sessions, Ryan, Boxer, and the list could go on a couple hundred names. They are the ones that are ambitious and will sell their kids souls for more power. They get rewarded for playing by the machine's rules by getting assigned to those powerful and prestigious committees. Its how the game is played. The ones you say are in it for the right reasons are usually long gone long before they ever get to that level.
And for the record.....the Meltdown lasted 4.5 hours before I even wanted to hit it again. Amazing medicine!