To give more financial support, you have to do independent, uncoordinated campaigning for the candidate. So you can spend a million dollars on ads saying to vote for a candidate, but you can't give that money to the candidate's campaign and the candidate can't coordinate with you. This is what Super PACs do.
I only write this because a lot of people are unclear on the rules. I'm not making an argument about billionaires.
> In fact, not a single coordination investigation has ever resulted in a PAC being fined.
I'm not naive enough to think communism is a magical answer (but Cuba is not some A/B experiment - the U.S. in particular has done a lot to make sure Cuba didn't succeed) - it ends up concentrating the wealth too. I would favor some form of democratic socialism, with leaders who can be kicked out if they abuse their power and limits on the influence of rich individuals and corporations.
On the latter, I think we forget that corporations are a legal construct intended to benefit society by allowing risk pooling - they are not people and should not be considered as such for things like free speech rights. Corporations should not be allowed to make political contributions in any way.