The US is an flawed democracy.

I personally rate it at 5/10 in the democracy scale (ranging from -10 to 10 where -10 is a totalitarian regime and 10 is a flawless democracy)

One of the major flaws is First Past The Post voting system, this results in 2 major parties, one of which is obviously worse than the other. The major parties are heavily influenced by rich people. Primary votes are still legit for most races, but money can buy propaganda that sways votes, but ultimately its still the voters choice. Voters are just easily manipulated, unfortunately. In terms of presidential primaries, those are very very flawed since there are superdelegates. After 2016 Democratic National Convention, the convention rules are changed to remove superdelegates from the first round of voting, making it much less flawed, but still, money can buy propaganda.

That said, AOC ran against a status quo democrat and won the primary and went on winning the election. Other progressives could do it too. In the presidential primary, its harder, but as long as the democrats don't change the rules again, its possible. In non-presidential primaries, they are governed by state laws, so its even harder for a party to unilaterally change the rules. Currently, all non-presidential primaries are all decided by First Past The Post who ever wins most vote become the party's nominee. Money can sway minds, but with enough support, the propaganda can be overcome, as AOC did.

The US was way worse in terms of democracy in the early days. I'd rate it at 1/10 democracy in the early days, where only white male landowners could vote. Eventually all white male could vote, then Black men could vote, then women. Americans have more rights today than in the country's beginning. A revolution could risk all those progress made.

Right now I see a path to fix the issues:

Replace First Past The Post with Ranked Choice Voting

Eliminate the Electoral College, replace with Ranked Choice Popular Vote

Abolish the Senate and give its powers to the House

Make the House use Proportional Representation

Overturn Citizens United decision

Overhaul money spending in politics