The far left doesn't understand history objectively to say that revolution is needed. A revolution in advanced economies does not go leftward – because the overwhelming majority of people in an advanced economy have too much to lose with the revolution. Anyone who's looked at which direction revolutions went during the 20th century would recognize that left-revolutions emerged largely in countries that have had their economies remain relatively pre-industrial, or early-industrial, where the bulk of the people would stand to gain from such a revolution.
64.2% of Americans own their own homes. 25 Million Americans are running their own businesses. A left-revolution would fundamentally destroy this. 70% of Americans consider themselves middle-class, and it's the middle class that would stand to lose the most out of any left-revolution.
Civil unrest in advanced economies results in a demand for order, people are far more willing to support political candidates that promise order and guarantee to preserve the existing interests of the middle class.
Nor would having working class people run for or occupy public spaces would solve the issue – as long as there exists a legal framework for people who occupy political spaces to advance their own interests. In many local elections, and I'd argue, in the majority of local elections the pool of candidates tend to be from the exact backgrounds you describe.
While the problems are vast, the most important change that can happen to Americans is a shift of focus of what politics are important. Federal and national politics currently take overwhelming center stage despite often having little impact on people's lives. Meanwhile local politics tend to be ignored, dismissed, leaving an entire system of politicians that are able to maintain their positions with little to no effort while impacting the local population far more.
Your city council has far more influence and impact on your daily lives than your Senator or President. But even that isn't the end-all-be-all solution either, if you have a population that is entirely ignorant about the long term effects of the things they vote on.
Personally. I am very much into the idea of Allocative Voting System – instead of voting yes or no on particular issues, a person allocates a set number of votes on issues that are most important to them. This seems to be a far better model about understanding what the current populations' interests are. For example, say you have 10 votes to allocate on 3 issues: Environmental, Homelessness, Taxation, well, for you, it's more important to deal with the environmental issues so you allocate 5 votes into Environment, 3 into Homelessness and 2 into taxation. That shows you, as an individual voter, have a far better preference that the government deals with environmental issues first.