I understand that you can look at this in a way that makes it seem like Apple's tight control over iOS is equivalent to Google's tight control over Android, but there are some key differences:
a) Android has market share dominances (likely around 75% in Europe in 2018)
b) iOS is not made available for other companies to use
You could make arguments that iOS behaves unfairly to third party developers and end users, and there are some decent arguments to be made there, but none of them are relevant to antitrust law because a) means there is no market dominance to abuse with, and b) means there are no competitors to be abused.
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You said "Most phone makers don't [skip Google services] because customers prefer the Google services, but that's not Google's fault". I think this gets to the heart of the disconnect between your stated position, and the legal reality here (IANAL though).
If Google's services are supreme because of user choice, then Google should require no legal arm-twisting to push those services onto devices.
Instead, what has happened is that Google has over-reached with its Android services contracts (one example - if you want to use Google services on one Android phone, you can't make a second Android phone that uses your own services), and that is what the EU is tackling here.
You know that Samsung has their own app store, right? By your explanation that wouldn't be possible because they also ship the Google Play store. But it is. Samsung replace many other apps too. What Google requires is that their services are available, not that others aren't.
The different stories people are telling here about why Google is "abusive" don't correlate with the realities of how Android licensing actually works.
Also since when is 75% market dominance? 75% is popular but that's still a quarter of the population successfully choosing an alternative.
Samsung phones are very often dinged in reviews because they ship a confusing mix of Samsung apps that duplicate the functionality of Google apps. I wouldn't be very surprised at all if Samsung would prefer to just ship their Calendar/whatever app, or even entire phones that only contain their apps/services, but they can't make those choices.
Regarding the 75%, please bear in mind that that is across the total market, which covers a very broad range of price points. Apple may have ~25% share, but that is skewed almost entirely to the top end of the market. In the low end of the market, Android would be nearly 100%.
So what you saying "one example - if you want to use Google services on one Android phone, you can't make a second Android phone that uses your own services" is wrong then?
No, it's not wrong. Samsung is allowed to add its own Calendar/Calculator/whatever apps, and their own App Store, but they are not allowed to remove Google's ones without dropping every non-AOSP Google app/service from every one of their android phones.
a) Android has market share dominances (likely around 75% in Europe in 2018)
b) iOS is not made available for other companies to use
You could make arguments that iOS behaves unfairly to third party developers and end users, and there are some decent arguments to be made there, but none of them are relevant to antitrust law because a) means there is no market dominance to abuse with, and b) means there are no competitors to be abused.
---
You said "Most phone makers don't [skip Google services] because customers prefer the Google services, but that's not Google's fault". I think this gets to the heart of the disconnect between your stated position, and the legal reality here (IANAL though).
If Google's services are supreme because of user choice, then Google should require no legal arm-twisting to push those services onto devices.
Instead, what has happened is that Google has over-reached with its Android services contracts (one example - if you want to use Google services on one Android phone, you can't make a second Android phone that uses your own services), and that is what the EU is tackling here.