Let's not mince words; the "option" you are referring to is to throw away your iPhone and buy a different device. The fact that this is the only path of recourse is the obvious reason why Apple is being investigated multinationally.
Users don't have to be opposed to a monopoly for one to exist. Customers loved Bell telephone's monopoly, because Bell gave their users free long-distance calling. That love did nothing to stop what the government did next.
Users "throw away [their phone] and buy a different device" basically every 2 years, anyway. Apple's policies haven't changed significantly, and their market share among mobile devices has stayed between 11 and 25% for 10 years now. Their "monopoly" is limited to what runs on the devices they sell, and its impact on the web is at worst a wash, and at best good for maintaining diversity among web engines.
Were iOS to represent an impactful plurality of mobile devices, I'd agree that there's monopolistic potential, but right now this is just a case where everyone (users, competitors, and government representatives interested in "sticking it to uber corporations") are all incentivized to push for legislation/regulations of this sort.
> Users "throw away [their phone] and buy a different device" basically every 2 years
If the DOJ's accusations of lock-in are true, then it's kinda a moot point. Perhaps even more criminal on Apple's behalf.
> its impact on the web is at worst a wash, and at best good for maintaining diversity among web engines.
It is not. Apple deliberately ignored PWA functionality for a decade until regulators threatened them enough to add it. They have dragged their feet supporting actual third-party browser options[0] and undeniably harm user freedom in the browser market.
"at best", Apple is using an illegal double-standard to prevent Google Chrome from competing with their underpowered browser. It is a pathetic plea to avoid competition, which is inexcusable no matter how powerful Google is. Realizing user harms to prevent a theoretical problem is not an excusable pattern of behavior - the DOJ and EU are absolutely correct in their judgement. They'll likely be right when they implicate Google too - but that's a different discussion, and entirely different harmful business strategy.
Let's not mince words; the "option" you are referring to is to throw away your iPhone and buy a different device. The fact that this is the only path of recourse is the obvious reason why Apple is being investigated multinationally.
Users don't have to be opposed to a monopoly for one to exist. Customers loved Bell telephone's monopoly, because Bell gave their users free long-distance calling. That love did nothing to stop what the government did next.