Microsoft was ruled an abusing monopoly (though the remedies were exceedingly limited).
Google is presently operating under a US DoJ consent decree. I'd have to check what the status for Facebook is. IBM saw its court actions. AT&T was a regulated, monopoly-abusing entity from the 1910s, and the only reason you're making heavy use of Unix-based systems today is that AT&T's 1949 consent decree (one of several in the company's history):
https://arstechnica.com/tech-policy/2011/07/should-we-thank-...
There were similar battles involving Westinghouse, Edison Electric, RCA, NBC, Xerox, and Land, in the tech field, and Standard Oil, numerous railroads, etc., in other fields.
The reality of the present is that Microsoft is still at it with their telemetry, forced upgrades and piggy backing of things that further drive their business on what are supposed to be security updates.
Well, let's revise your original words to take that into account: "Not many companies have such a sordid history of unfair competition as Microsoft does, merely almost all of the ones of the same size and influence."
Rather takes a lot of the rhetorical weight out of it, doesn't it?
I think it was Eben Moglen I heard point out that the places in which software freedom has won over Microsoft turned out to be easier than might have been suspected 20 years ago because it was easy enough for free software to outdo Microsoft garbage. Now, with Google, Amazon, and Apple the power issues remain but the products they make are so much better, it's much harder to compete.
It was easy for Firefox to beat IE, not so easy to beat Chrome. And lots of people who were pissed off about Microsoft's power abuses give Google a pass because it's easier to go explore Google Earth and ignore the issues compared with just frustration about Microsoft's shitty software. Unfortunately, Microsoft is just as into abusing their power but has learned to be a bit less shitty in their product quality…