Don't forget the role of voters, though.
If a candidate had no chance to appeal to voters then nobody would write them checks in the first place.
We elect these people. We actively go out and pull the level to vote for them.
If we would stop voting for bad people, the money for bad people would dry up as they would be bad investments.
So long as we can be relied on to hand these people power they will keep running, keep fundraising, and keep getting into office as we empower them.