Sorry factual correction. De Beers was created shortly after Rhodes left office.
Find an example of a monopoly that was created by some method other than political influence, and I’ll concede the point; otherwise you may consider conceding mine: Where you find a monopoly, you find government interference in the free market.
U.S. Steel was once a monopoly that the federal government tried to break up. They failed, and today U.S. Steel supplies a tiny fraction of the steel we use.