> The American political system has been very successful in telling its people that the only acceptable way to show discontent and enact change is by voting on elections.

Has it? Because I recall a bunch of people gathering in the wrong building on Jan 6

Very does not mean perfectly.

... yet still tens of millions of eligible voters don't even bother

the country is very low-density, there's no one obvious point to protest (there was Occupy Wall Street... and then the Seattle TAZ and .... that's it, oh and the Capitol January 6th)

the country has a lot of experience "managing" internal unpleasantry, see the time leading up to the civil war, and then the reconstruction, and then there was a lull as the innovation in racism led to legalized economic racism (the usual walking while black "crimes", vagrancy laws, etc), and then the civil rights era, with the riots, and since then police brutality is used as a substitute to training and funding

I think a general strike might be effective for low-density places, though that requires enough people taking part to make it truly effective. That way you don't need an obvious place to protest apart from your workplace and it'd be a non-violent protest that would definitely get the attention of the wealthy.