Of course there are other problems with a modern system which places profit above the interests of the people. But the problem is one of conflicting interests. The US was founded by people who realised they had conflicting interests with the British crown, and they managed to do their best to unite all those who could benefit from independence; even still many were not convinced.
Conflicting interests lead to France supporting the war of independence, and essentially single-handedly swinging the war in favour of the colonies. But this conflict of interest remains. Tenants, slaves, workers, and 'Indians' all had conflicting interests with the wealthy, land owning, slave owning, factory owning classes.
And to this day we see America divided along these lines. There is no universal health care, no free higher education, no protection of indigenous rights. There is limited protection of rights for women, people of colour, and the poor.
I'm not just talking about slavery and genocide; I am talking about the exploitation of workers, and tenant farmers (like these: : https://libcom.org/history/articles/anti-renter-movement-1839-1846 ). Capitalism, and 'market forces' are directly responsible for the deaths caused during the Irish great famine, and the 1876-78 great famine in India (both under british rule). And yet this ideology is still considered sacred for many US politicians (while Communism's millions dead due to famine is used to scare children).
Wealth inequality is growing wider, and the FBI intentionally targets left-leaning organisations with tactics to disorganise them. Trolls, roleplayers, anything they can do, not limited to the assassination of key organisers in the 70s (see cointelpro) and continuing to this day ( see: https://www.theguardian.com/commentisfree/2012/dec/29/fbi-coordinated-crackdown-occupy ). You will note these are peaceful US citizens being denied their right to protest - because they are deemed to be a threat to the status quo.
Anyone who tries to upset the powers that be is subject to this kind of repressive actions. Whether that was the anti-war movement during the Vietnam war, or the civil rights movement, or the occupy movement. Effective political protest is suppressed. Organisations are targeted. Power protects itself. And those whose interests conflict with the powerful are alienated, marginalised, and subject to arrest.
You can see it in low voter turnout. You can see in the increasing income and wealth gap. And you can see how Trump has scapegoated minorities to re-direct the anger of millions of voters at 'illegals' and Muslims.
People are angry, and they should be angry; and solidarity between poor angry americans is the last thing the power that be want.