There are handlers too. People who make sure those calls get made.
The DNC, and likely the RNC, has a party quota, and that runs in addition to whatever getting reelected will require.
On those calls, everyone knows what needs to happen:
Those people of means need to be heard. They also want stuff to happen.
The politicians need dollars, favorable press, testimonials and help paying for staffers who take the incoming calls, faxes letters and whatever else comes in from the/ public. Those staffers often write laws and do research too.
The lobbies play off all that and are able to bring money and whatever else may make sense into the equation.
You are right in the strict sense of dollars not driving choices directly.
The system that does drive choices is packed to the gills with grift, old money, corruption, and in general, people of means and corporations driving most decisions.
Transactions called bribes, that are criminalized in much of the world, happen here daily!
We are among the most propagandized people in the world too.
I forget the study, but it basically showed how voters feel about an issue can count, except economic issues where we basically do not count in all but the most extreme sense.
My take after a good decade of activism and some access to this stuff is a fair bit less charitable.
And yes, we both miss the mark, and that is not good news.
The reality is likely more insidious and toxic to ordinary people.