Of course they're wealthy. Only wealthy people RUN for Congress, because everyone else seems to despise it.
In the grand scheme of things, $93 million is not a lot of money (a tiny, tiny percentage of federal spending) and cutting it out would:
a) Enormously increase the proportion of millionaires in Congress, because nobody else would be able to afford a full time volunteer job, and
b) Have no impact on the deficit.
Also, guess who has to vote on abolishing the salaries of congressmen?