I don't believe donations or corporate backing had anything to do with Trump, for example, winning. Trump won because he genuinely appeals to the average voting American. American voters are willingly choosing to support these politicians and all of the consequences that entails.
For the president election, maybe, but without corporate backing of the GOP he would have to face an adversarial congress. Or at least, that’s the hope
Both can be true.
To discount advertising and manipulation in this context amounts to conspiracy theory in my opinion.
You can believe the latter but the former ignores everything we know about the effectiveness of advertising.
And also about the targeting of swing districts.