To believe that the concentration of wealth in the hands of the few doesn't matter in a democracy is to believe in a fairy tale. Let it be known that concentrated wealth matters, and to the degree that those with wealth make it their point to get what they desire to get, so as to maintain, or even better, enhance what they already have, is going to definitely have negative consequences for the people, which are inimical to a democracy and hence bad for the general public, who are the ones that will suffer the most for not having a voice, and thus not having any influence upon the most important public affairs settled upon.
While it is true that we do have a democratic vote in which some of the most important legislative propositions are put up to vote by the people, and the people are also the ones that through their vote select their political representatives, it needs to be acknowledged that the side that expends more money on a particular proposition or candidate is often in the driver's seat of obtaining the result that they desire to get. That is to say, the influence of money in a democracy absolutely makes a difference in the results obtained, which is why there should be more robust guardrails in place to not just identify who and what is providing the funding for these things but also to limit how much money can be designated from one entity to those propositions and to politicians, because without appropriate guardrails, those with money are going to see to it that they have an undue influence upon getting the result that they deeply desire.
Indeed, whenever the people's vote is essentially heavily influenced by those who are gifted in creating ads for a price that guide people to a certain conclusion isn't good for society, because the decisions so being affected have often been shaped by the rich and powerful for their benefit, which signifies that the only real workaround therefore is to limit the influence of those that are super-rich in these decisions. Further to the point, the only way to reduce the overall power impressed upon the people by the super-rich is to appropriately tax these entities and to not permit wealth to pass on essentially untaxed or lightly taxed from one generation to the next, because that is especially damaging to democracy, for it leads to the type of death spiral which provides the people only with what amounts to being a democracy in name but not in principle because their vote and the result thereof have highly favored the super-rich at the expense of the general public.
Look, those that are well connected are in a very good personal space, and those that are super-rich are typically very motivated to see that they, at a minimum, maintain their status and thus are determined to see that the democratic vote and all relevant propositions go their way, and quite apparently this is readily happening because the super-rich in America are increasing their lion's share of the wealth, year after year, at the obvious expense of those that collectively are regressing, which clearly reflects that our democratic vote as currently structured is deeply flawed and needs to be revised for the better.