It didn’t have to be that way. If Apple had sensible policies that stand the test of regulatory scrutiny this wouldn’t happen. Now that lawmakers get involved I will expect the worst outcome for customers, or as you succinctly put it „we lose“.
If Apple allows external IAP, but _also_ requires strict dispute resolution and simple subscription cancellation, that would probably be deemed anticompetitive as well, even though it's thoroughly pro-consumer.
The problem here is that the regulatory scrutiny is only on one dimension, not the full picture. And in the full picture, Apple's policies are eminently reasonable—if their fees are a bit high.
Thus the looming changes: Apple requires account deletion within apps in AppStore starting January 31 https://news.ycombinator.com/item?id=28776960
Why would that be considered anticompetitive?
However, the same people who say that it’s anticompetitive for Apple to control the payment flow are likely to say that _any_ impingement of Apple on the customer relationship is anticompetitive. These are the people who don’t actually _care_ about the customer relationship, like the NYTimes subscription department, or the companies that bank on customers forgetting to cancel their subscription for months at a time or not wanting to spend time on the phone to fight over a $1.29/month subscription fee.
IMO, antitrust/anticompetition investigations tend to be _far_ too limited in their scope (they look only at one or two aspects and not the big picture of what's happening). I remember a few years ago when Apple had worked with publishers to establish a new standard ebook contract for publishers and marketplaces. It was one that would have (slightly) raised the prices of ebooks, but replaced the unilaterally imposed contract that Amazon provided. Apple got in trouble over it, even the result would have been a _better_ and more _competitive_ marketplace and not one controlled by Amazon.
I have opinions on what should be done with the app stores that would _probably_ fix a lot of the issues, but any changes to the app stores need to look at whether it would be a _better_ situation for customers or just a more lucrative situation for publishers. And the customer impact would not just be measured on “choice”, but on overall price/privacy impact.
Measured by that, there’s no question in my mind that Apple’s doing a better job than people give them credit for.