> Companies will want it, but I'm not sure users will.
Is Amazon was allowed to run a store on iOS, Android, and Fire devices, and if you bought an app you were guaranteed the equivalent version on other devices if it existed, I think there would be a lot of incentive for people to use it. I wouldn't necessarily prefer Amazon be the entity running it in the end, but they're probably best poised to do so with customer trust.
> Apple does a really good job of warning me, I feel, and centralizing subscription cancellation etc., and that's huge.
If there was actual competition between stores, this could be an item of competition, and a minimum acceptable level of support for this might emerge in the front runners. Amazon is already pretty good at making customers happy, this might be something they'd happily take on (and don't they already do subscriptions for magazines?).
The whole problem is that people keep looking at this as "Apple may be bad at X, but they do Y really well and I don't want to lose that" when they should be looking at it as "Apple is bad at X, maybe if they get some competition they'll do better at X, and Y will still be done well by them".
I can't understand why anyone would assume Apple having competition on their platform would make them worse. They would actually have to address problems for once otherwise worry about losing people to other stores, not entire phone ecosystems which require multiple hundreds of dollars and losing access to all your purchases.
If some company is really trying to get out of the Apple controlled system not because of costs but because they really want access to your personal info or to make it hard to stop paying them, maybe they should be allowed to leave and they can get less customers and hopefully change or die. Chances are they're trying to figure out the info using other methods right now anyways.