Campaign contributions don't really decide elections beyond a certain minimum level, though, particularly if an incumbent is running.
Look, I agree that policy in general is tilted toward the interests of the rich. I don't see campaign contributions being a part of that. For one thing, almost everyone who seriously runs for office is rich themselves, and mostly or exclusively only knows other rich or at least upper-middle people in an intimate way. And then, yeah, big donors are going to get their calls taken, but what happens after those calls begin is what's really important. Think of how your own views are shaped.
No offense, but this ties to discussions I've had with
@IngaVovchanchyn and
@Cajun.
People who really study what active steps people can take to make winning elections more likely are pretty much stumped. William Goldman's summary of the entertainment industry ("nobody knows anything") applies to the political one, too. Studies that attempt to answer whether this technique or that one actually works almost always show being "no, or the effect is too small to be identified." But regular people are really convinced that they know what works (generally--do what I like, and you'll win elections). I think it's really an issue where the more you know, the more humble you are.