Why did labor unions such as the knights of labor, the afl, and the aru have such a difficult time carrying out a successful

The Knights of Labor collapsed after the Haymarket Square bombing. The group consisted of unskilled labor and skilled labor. The skilled labor decided to leave the Knights of Labor, forming AFL, because they felt that teaming up with the unskilled worker was more of a liability. However, the AFL and other unions eventually wore out because they made little to no progress in industrial America. They held thousands of strikes which pretty much led to dead ends and eventually the union dwindling.