What a lot of people don’t seem to understand is that propaganda doesn’t cause beliefs, it focuses and amplified beliefs that preexist at least in nascent form. The Koch brothers would have no power if there weren’t people ready for their kind of message. In fact this is a good example. The Koch Brothers were against the Trumpian turn in Republican politics and spent heavily against it. How did that work out for them?
Sorry money == power is too facile.
The fact that some rich people only get part of what they want because they're opposed by other rich people, does not mean that their money didn't get them power. The Koch brothers got a lot of what they wanted.
And even if poor people, if there are enough of them and they are sufficiently organised, are able to oppose rich people, that still doesn't mean that the rich people don't have more power individually. Their resources make it much easier to organise, to buy influence and support, to reward politicians who legislate the way they want.
In the US, even more than in other countries, money is absolutely power.
Not every billionaire uses their money for that kind of power, but some do, and it hurts democracy when they do. In fact, it's even been argued that legitimate philanthropy is undemocratic, because it's rich people deciding which problems society will fix, rather than a democratic process.
If money only provided luxury, people would have less problems with this inequality. And people would probably be less interested in amassing more wealth than they can consume.