At the height of the Industrial Revolution, some of the most financially successful capitalists were known as "robber barons." These capitalists used their company-owned land and capital (factories, railways, company stores, equipment, etc.) as leverage to control a labor force that had minimal leverage because they owned no capital. Long hours, dangerous and unhealthy physical conditions, child labor, lack of job security and discrimination were the norm for the rank and file worker.
The situation was out of balance. Its backlash resulted in the rise of labor unions and the development of Marx's fundamental belief in state-owned, rather than privately owned property, establishing the Communist version of socialism as a political and economic ideology.
Obviously, neither of these systems, situated at extreme opposite ends of the bell curve, was the answer. Capitalists often abused their power. Employees developed distrust for management. Pure socialism, on the other hand, disincentivized workers by placing them in situations where they could not directly derive a benefit from their efforts.
Labor unions, and the often corrupt misrepresentation for which they're known, were not the answer either. They were (and still are) makeshift approaches to solving symptoms, rather than a treatment for the underlying problems.
Robber baron-controlled capitalism, pure socialism and labor unions were all extreme solutions. Yet these extremes provided the tension needed to evolve the workplace as an ongoing lab to encourage new and better ways to live and work.