So, in 1776, the United States declared its independence from Britain. We saw King George III as a tyrant and a bully, so we were like, later, guys. What's interesting is that the American Revolution was all about casting off the oppression of a single, unified symbol of injustice: the King and his government. What is challenging about imagining a socialist revolution à la Upton Sinclair is that there is no single problem. It's the whole economic system of the United States – the banks, the marketers, the factory owners, the foremen, the managers, the bosses, the stores, the judges, the incompetent government inspectors, the rigged elections, everything – that keeps the workingman down. How do you rise up against a decentralized system of power? Perhaps it is the sheer scope of the problems Sinclair points out that explains why The Jungle is pretty much only remembered for one thing: meatpacking. Issues in hygiene and food safety were one thing that progressives could address immediately through federal legislation – their King George III, if you will. Larger problems like poverty, illiteracy, and prostitution can't be solved with the establishment of a new federal agency; these problems endure today.
In The Jungle, there is no legitimate avenue for poor people to increase their power. Jurgis must resort to election rigging and selling out his union in order to achieve his temporary status as boss of the hog trimmers later on in the novel.
The Jungle repeatedly illustrates the saying that all power corrupts absolutely. There are no characters in positions of power over their fellow men who do not abuse this power in some fashion.