One of the downsides to that rule, is that it heavily favors incumbents who have big donor networks in place. And it imposes a big cost on the new players, jus

One of the downsides to that rule, is that it heavily favors incumbents who have big donor networks in place. And it imposes a big cost on the new players, just to get the donor networks. It's one contributing reason why it often takes a self-funded millionaire/billionaire to unseat them - or get real traction in a campaign.