The problem is that we have a system of elections that encourages campaign spending. Were we to change how we elect candidates, the problem will go away. This has already been shown mathematically-
https://www.researchgate.net/publication/228955551_A_FISTFUL_OF_EUROS_INCUMBENT_AND_CHALLENGER_CAMPAIGN_SPENDING_EFFECTS_UNDER_THE_SINGLE-TRANSFERABLE_VOTE_ELECTORAL