All democracies have suffered from oligarchical influence, be it in the form of people with money or common interest groups banding together. The Romans and Greeks made your complaint, and in 5000 years, democracies will still be making it. Chief Grog once said to Medicine Man Ug that he couldn't believe the neadrethals wanted more mammoth meat.
Not shocking you've completely missed the point.
The point isn't that money corrupts and always has. It's that our system of government has changed without our consent. That's not the same thing as "influence".
We no longer live in the democratic republic outlined by the Constitution. This is not even up for debate as it's a fact. We've codified bribery into the legislative and executive branches, increased the authoritarian scope of the presidency, made corporations people, made money equal to speech, created the world's most advanced surveillance state to keep the plebs in line (and more importantly, to blackmail the elected officials who might dare to march out of step), and completely disenfranchised the majority of American citizens... all within the last 16 years.
All without a vote, a constitutional amendment, or even a national discussion on the topic.
Your defense is, "that's how it's always been in history and how it always will be" -- which is not only missing the point, it's dangerously naive.