There is a difference between monopolies and anti-trust. It is not, nor should it be, illegal to be the only serious contender in a given category.

If I make widgets for arcade machines so well that I drive all the other arcade machine widget makers out of business, that's normal commerce.

Antitrust is when I gain and maintain that advantage through specific practices detailed in the legal code

Monopolies are only broken up when it is of grave public interest to do so. There are industries I believe have monopoly/duopoly problems and should be broken up. "Hosting videos on the Internet" is not one of them.

Again, trying to say "pharmaceuticals shouldn't be an oligarchy/monopoly, which is proof that nothing should be" is not good logic

You should look into the history and breakup of the Bell telephone company for context on when a monopoly is broken up and why

How are you defining "should be" anyway? Your personal opinion? What profit margins should be considered okay and for which products or services?

You need to pick which things are important enough to forcibly break up, and everything after that is fair game, regardless of what you think is healthy for the market. Otherwise you're just talking about "I don't like the leadership of that company, they're bad people" at which point your problem is about, like, specific people's ethics.

I hate that those people succeed, and there are things I think we can do to mitigate those problems, but "Google bad, don't let them secure their products or help others secure theirs" ain't it homie