You could have said the same thing about Windows during it's antitrust case.

Fat lot of good that logic would do Microsoft when they were deliberately gimping competitors.

You couldn't have, though. Market share was a part of that Microsoft decision. At the time, they had 90-95% of the global market share — there were very few competitors. Apple has a higher though still in the 50s percentage-wise market share in the US, but a 20-30% share globally. Alternatives are much more viable in Apple's case, and often cheaper. You have to want an Apple device to get one, and it's very easy to get an Android instead and not lose out on any important software or functional ability.

In addition, I think Apple has so far somewhat successfully argued that they have reasons for restricting their ecosystem that aren't just a thinly veiled "because we want to crush competition". They argue that their devices are safer to use, and that allowing arbitrary software full access to the system would compromise that. Similarly, they limit third-party software from tracking you. They certainly aren't saints, and I disagree with a many of their choices (their app store cut could've decreased long ago, for one, and they're now adding ads into their own services) but they often seem like the only large corporation of their kind that even tries to have a set of beliefs and care about their users, and I think intent should matter.

I personally like that there's one popular ecosystem that has a particular perspective, and another competing popular ecosystem that has a totally different perspective. If you think all of the above is bullshit and Apple sucks, you're free to use Android and install exactly what you want on your phone. I've never really understood why folks are so adamant that this alternative should not be allowed to exist.