The US is first and foremost a capitalist society. One could attempt to argue your characterization that it's "democratic" but in my opinion, that won't stand in the face of of Burwell vs Hobby Lobby and Citizens United vs FEC.

If you think Musk is going to defeat capitalism to the point that commoners are heard in the town square, unfettered by the wants of advertisers and media conglomerates, I'd say your chances are better praying that his next venture is a moonshot for time travel, destination circa 1600. Or before: one of the first tunes I learned on the violin was an advertising jingle popularized around then.

No, Musk doesn't want the commoner to be heard. He wants his opinion to have center stage. He's certainly not going to undo the grip that capitalism has on the public sphere. He's just another moneyed elite.