I don’t think it’s about principles at all.
This all boils down to power, and who is able to get their way and get what they want, consequences to everyone else be darned.
If these people were so interested in enabling competition, they would have opted for a platform which enabled functionality like sideloading and third party app stores right from the very start. Instead, they, like so many other people, opted for a close ecosystem and have reaped the benefits of the tight integration and now that they want more, a narrative is being spun about how we are all prisoners of Apple’s walled garden and only government regulation can save us from ourselves.
Nothing wrong here, IMO. Let’s just be honest about the possible ramifications, rather than try to hand wave everything away and pretend that everything will be a bed of roses and that there will be absolutely zero downsides whatsoever.