I believe consumer choice is essential to making markets efficient. I think more of it is better. For example I also think we should have a right to repair, so companies are forced to give me a choice to repair instead of throwing away and buying anew. Sure, you could say I could just vote with my wallet and not do business with any company that does not prioritize repairability. But in reality that doesn't work because the vast majority of companies don't do that because it's in their interest that I need to buy a new thing every couple of years. So I need a right to repair law to give me, as a consumer, some reasonable choices that it's not in the companies' own interest to give me.

Exactly the same thing goes for what I do with the devices I buy, and what software I install on them. It's not in Apple's interest that I have a choice of what source of apps I use - but giving me as a consumer that choice would expand the market (e.g. by making it possible to sell an app-based service with a 20% profit margin - currently if you tried to make one, you'd lose 10% on every sale). So yes, consumers currently have a choice of which side of the duopoly they want to live on. I believe more choice would be better, both for consumers and for the ecosystem as a whole.

You only have that right in advance, though. If I get an iPhone and buy a bunch of software on it and then 3 years later Apple Changes The Terms Of Our Relationship, I don't have any ability to migrate my data (let alone my purchases) to another platform. Not only do I have to buy a new smartphone, I have to re-buy my apps even if those apps are available on Android. Even if the app's developer wants to give me the app for free on other platforms, they can't, because Apple refuses to give developers any information on their customers. This came up previously when some OS X software had to leave the Mac App Store. Likewise any music or videos I bought on iTunes won't migrate over to my Android phone - in the era of physical media this wasn't a problem, you could pop your CD or DVD into any player you want so you had true freedom.

Windows and Mac and Linux environments are not sandboxed like this either. All my data is files in folders, and I can export it as I like to another machine.

Cool, how do I install it on my iPhone? The one I bought with my money?