I realise a lot of people here just like to use words and make up definitions, but surely there should be a limit to how far one's dislike for Apple allows them to hallucinate their own reality.
A vertically-integrated company is not a monopoly. Apple did not disincentivise developers from developing third party app stores for iOS because it's literally not possible. When people buy an iPhone, they are buying into the premise of how Apple has set up the App Store. The next key point is that Apple hasn't changed its policy after a phone has been purchased in order to drive out competition.
This is why Google was found guilty while Apple wasn't. The Google Play Store was accessible by many different brands and Google went behind their backs to alter its core functionality. There are two very different situations legally and I don't understand why people keep trying to conflate the two.
It doesn't matter that there are people who think that Apple has a monopoly on the App Store. It's irrelevant. If the conditions of buying an iPhone with the App Store rules haven't changed, then Apple is not breaking the law because people knew what they were getting into when they bought an iPhone.
Definitions are definitions, and Apple is by definition not a monopoly by any definition which matters. This is very likely why Apple chose to have their case be decided by a judge, precisely because they knew they had a very strong case which absolutely needed someone well-versed with the nuances of anti-trust law to be able to put aside whatever personal feelings they may have on the matter and fully comprehend.