It's also interesting that when Rockefeller dominated the oil market and standardized it, the price of kerosene dropped dramatically. Rather than monopoly being negative for consumers, the competition had actually driven up prices and lowered quality standards as competitors sabotaged eachother
I think that was a function of the phase of the S curve.
Also remember his tying: he controlled all the tankers so even if you competed with him in petroleum products he controlled your (literal) path to market.
