A winning Senator spends on average $10 million for his campaign. If he’s primaried the price goes up. (John McCain spent 23 million on his last primary fight alone.) A winning Representative spends, on average $3.1 million dollars, assuming no primary fight.
With few exceptions Representatives and Senators increase their net value exponentially above their “pay” during their time in office. They run, apparently, not for the pay but for the perks.
When they get out they get very high paid no-show jobs. The ruling class takes care of it’s own.