If politicians are denied chance to get silently wealthy on their positions, we will have different kind of politicians: not relatively benign fat cats who are after nothing but money, but ideologically explosive 'great leaders' who want to change the world in the name of their 'great' ideas (there won't be much reason to go into politics otherwise, if you can't make much cash there). Do you really want any of them?
Corruptioners are the best kinds of politicians you may have.
Well, I already have plenty of politicians representing me as a result of recent elections, and they belong to neither of the kind, as far as I know. Here in Germany we probably have few fat cats, but the 'great leaders' are political marginals. The politics are done by parties, which leadership periodically changes, and the government isn't run by a single person able to impose their will on other ministers.
Corruptioners are the best kinds of politicians you may have.