John D. Rockefeller, the "robber baron" monopolist who created Standard Oil in the late 1800s, was able to acquire 90% market share. We're told that he bought up all the competition and no one could compete against him. He was greedy and at his height, he owned 90% of the market share! Something had to be done!
Conveniently, this story leaves out the fact that he dropped the price of oil from 58cents to 8cents per gallon. Which is fantastically good for ALL industries and improved the quality of life of almost everyone in that era. Let alone saving the whales by making kerosene lamps cheaper than candles made from whale blubber.
Rockefeller did indeed buy up much of his competition. Let us pretend that he was a greedy capitalist who only bought up competition so that he could raise prices in the long run, and that all his competition wanted to sell to him, and there were no stubborn owners who didn't want to sell, etc, etc. Those with a shrewd eye may realize that his purchases are DEMAND for oil businesses. Predictably, supply met that demand. In fact, many successful businesses were created for the purpose of creating companies that were to be sold to Standard Oil. In this beautiful way, no person could possibly gain non-coercive monopoly by buying up competition.
Simply put: In a free market, buying out your competition is DEMAND for competition.
https://theanarchistlibrary.org/library/alexander-berkman-what-is-communist-anarchism