Facebook seems like the least of the big techs
that are the most abusive of monopoly
FB blatantly abuses its monopoly by trying to buy smaller competitors, and if that fails, cloning their products.
re: tiktok and clubhouse
I think the op made a good point about the Facebook m&a spree being put on hold due to their legal troubles a few years back and now can only try to clone/crush competitors now. They cloned tiktok and wouldn't be surprised to hear they have a clubhouse clone in the works.
That doesn't make a company monopolistic. Having a strategy that considers competitors and the whole market is just savvy thinking.
Monopoly is about the detail of how such a strategy succeeds. It isn't obvious that Facebook has a monopoly.
From where I sit Facebook appears the most brazen about their anti-competitive practices especially when compared to Google. Their tightly held walled guarden, forcing oculus to use facebook accounts, etc. Android allows 3rd party market places, Google's products in general have low switching cost (from gmail, calendar, etc to 3rd party stuff). Their ad network is pretty pervasive there and hard to escape just because of the size and Google's push for AMP on the web when so many were against it does seem like flexing their monopolistic strength.
Now if you talked about Onavo we might be on to something.