There's monopoly, then there's abuse of monopoly. When your marketshare is that big you have to be more careful than everyone else not to abuse your monopoly, but you can have a far lower marketshare than that, less than 50%, and still get nailed for monopolistic practices.
Monopolies can do good or bad. Standard Oil brought efficient production and use of materials, providing cheap oil to the masses. It deserved to grow big. The main people who lost out were the less efficient competition in the early days, but even then serious competition was already forming before the breakup in the form of Shell, Gulf Oil and others. IMHO, pure market forces would have killed the Standard Oil monopoly by the 1930s.
I agree.
When your marketshare is that big you have to be more careful than everyone else not to abuse your monopoly, but you can have a far lower marketshare than that, less than 50%, and still get nailed for monopolistic practices.
Can you give an example of a company with less than 50% of the market getting "nailed" with monopolistic practices. One of the tests for such judicial involvement is SHOWING that the defendant company is in a monopolistic position. Having less than 50% of the market would be prima facie evidence that they were not a monopoly.