What monopoly would that be? Apple quite literally advertises alternatives to its Messages app on the app store landing page.

How many of those alternatives come pre-installed and can't be removed?

How is that even relevant? The stock Messages app doesn't conflict with any of the other messaging apps.

Lawsuits on Microsoft & IE pretty well established that defaults matter for antitrust actions.

One of the remedies was to prompt the user to pick a browser at install time. Apple is literally advertising all of the alternatives in perhaps the most obvious way that they can. There's no trust to bust here.

IE had the majority of the market share on the most popular desktop platform (Windows). Neither Messages nor the iPhone are in that position. Phones are pretty evenly split between Apple and Google in the US (and it's more lopsided in favor of Google elsewhere). Again, by virtue of having competition and having that competition easily accessible there's no monopoly.

There's just a bunch of butthurt Google fanbois who are lamenting the color of… well the color of someone else's text messages on that other person's device. All received messages have a grey background.

For the sake of the argumt, let's say there is no monopoly, but a competitive landscape filled with alternatives and switching costs are zero.

Does that change my point about the difference in those examples?

You can get alternative SMS apps on iOS?