So if I buy a Macbook, we should require Apple to make available all software I had on my Windows PC? That makes no sense.
I never said that. My point is that moving devices isn't as simple as just buying a new one - i.e. it's not good enough to say just move to android (up to a point). There's nothing you can really do about it's just how software works.
To borrow an analogy from another post: If I buy a BMW and later switch to a Honda, do I get to be mad if some of the BMW parts don't fit?
You get to be mad if your third-party child seat doesn't fit.
I'm confused - what does the third-party child seat map to in the iOS world?
Third-party content purchased while using the BMW/iPhone that you want to use with your Honda/Android. Plenty of apps are cross-platform, like child seats.