The problem is that classical Marxism doesn't work. What seems good in theory has consistently failed in practice. The workers overthrow the old government that served the entrenched power interests and install a government that - with the power interests destroyed by revolution - instead fills the power vacuum itself and then serves its own interests. The "workers' governments" inevitably and invariably evolve into repressive totalitarian regimes more interested in their own survival than in the welfare of the people that they were intended to serve.