We have all been trained by progressive-dominated media, government schools, and even some of our "leaders" that a monopoly is a purely market-based entity and it's a bad entity. Well, not so fast. Let's take a look at what Merriam-Webster defines has to say about how a "Monopoly" is defined. Looking at the list, it is entirely in stereotypical ways and all of the entries are intended as condemnations of private industry.
One entry says "one that has a monopoly". Another entry says "exclusive possession or control".
This is plain garbage. A monopolist is a monopolist because they are a monopolist. That's basically what these are saying. Even the very first entry, which says "exclusive ownership through legal privilege, command of supply, or concerted action" is polluted. It kind of swerves into the truth with this "legal privilege" phrase, but that phrase is too loose to be useful considering the "or concerted action" nonsense it is connected with. It's the corruption of the language itself. Here is how a "monopoly" used to be defined: (source)
An institution or allowance by the king, by his grant, commission, or otherwise, to any persons or corporations, of or for the sole buying, selling, making, working or using every thing, whereby any person or corporations are sought to be restrained of any freedom or liberty that they had before, or hindered in their lawful trade.
That's really specific, now isn't it? This is Edward Coke's definition of a monopoly, in case you were wondering. In reality, the only kind of monopoly that can possibly exist is a legal monopoly. That is, for example, the Royal East India Trading Company, is rightfully described as a monopoly. It was never a monopoly because it was the only supplier in the field, it was always a monopoly because of the king's charter! But you see, progressives had to blow this definition of a monopoly out of the water because what does it do? It implicates them. Single payer healthcare, government schools, the TVA, utilities, the nationalization of the railways in 1917, the nationalization of student loans, etc etc etc. All of it are legal monopolies. Even where there is not a sole-supplier status, we do find monopolies. Fannie Mae and Freddie Mac both have a grant or a commission from the king by nature of their very existence. Both are monopolies - in this instance they would be a government sanctioned duopoly. Amtrak is another example of a monopoly. Ever wonder why you can't get CNN out of airports? Air travel is a government controlled monopoly.
In all instances, these government-dominated sectors were brought to you by progressivism. They want government, and only government, to control your health. To control your retirement. To control your food. To control where you can and cannot go via transportation. What you can or cannot see, or what you hear.
I suspect that the Sherman Anti-trust act plays a larger than life role in the re-structuring of the word monopoly, but I cannot say for certain when this ultimately took place. But I do know this. A definite answer as to "when" we went from a sane definition of monopoly and arrived at a pro-big-government definition of it would be to the benefit of constitutionalists and to the detriment of progressives.