It's perfectly normal that you have this impression of democrats and republicans simply negociating their share of the cake.
There are two major problems in the american politics that completely gridlocks your political panorama.
The first one is your election system. Indirect election is automatically killing the people's importance because why care about hundreds of millions of votes when your only need a hundred (or so, i don't know how many great electors you have) from the right people ? Your great electors aren't even forced to vote how their electors want them to, how do you want any shred of democracy to come out of that ? That's the main reason hearing the word <<democracy>> in an american's mouth always makes me laugh (no insult intended, it's just that many of them speak of what they have no clue of and even go as far as think they're the best at it).
Second one is bipartisanship. I mean how the fuck do you want them to be honest and opposed when all they have to do is strike a deal among themselves to get what they want ? American politics is already completely standardized when it comes to ideology, so you don't even have a real deep rivalry between your parties.
And then oyu only put two in place ? How do you want a politician to be honest (at all, first-hand, but let's skip that) when he only has one opponent who's not so different ? Of course they strike deals to get what they want, it's easier to talk than to fight.
It's like an oligopoly (just a few businesses holding a whole market), why compete when you can just negociate among you few to get even richer that you'd be in competition. No need to fight lowering prices, when everyone can agree to raise them with no backfiring whatsoever. And on the american politics market, you only have two businesses.
Your system is not the worst, Italy has, in my view, the worst political system ever.
And don't get me wrong, i'm not sayong french system is perfect, far from it, but at least we get a glimpse of what an ersatz of democracy is.
Sry if i sound rude/Blunt but i'm really excited to finally see an american question his country's regime.
Never overestimate mankind.