Under communism, workers own the means of production and all of the profit their labor creates. Centralizing business into a single private monopoly whose profit is entirely controlled by shareholders is the exact opposite of communism.
You're correct that monopoly leads to a degradation of products and services, but that's a flaw in capitalism (specifically the myth of the self-regulating free market ideal that eschews proper regulation in favor of the "invisible hand.")
You're correct that monopoly leads to a degradation of products and services, but that's a flaw in capitalism (specifically the myth of the self-regulating free market ideal that eschews proper regulation in favor of the "invisible hand.")