Apple knows they're not allowing the Dancing Pigs into the iOS spectrum and with that comes restrictions which will frustrate some people. They don't advertise anything different from that. So far, they've made 800 million iOS customers really happy at the expense of maybe 100,000 code monkeys.
The point remains that Apple could have allow the option of leaving the walled garden, and 800 million people would still be just as safe as long as they didn't leave, and they wouldn't leave.
Android allows you to leave the walled garden, and the VAST MAJORITY stay inside by choice, or if they step outside its just to add a 2nd trustworthy walled garden. (e.g. humblebundle, the official samsung app store, etc)
My bigger problem with Android is who the mother ship is; Google, which has turned into a spy agency in their own right. They've brilliantly created a portable vehicle to map and catalog your every move and view. Their business model is to destroy your privacy and sell what they learn about you to marketers, the scum of the earth, without restraint or remorse. Apple, on the other hand, is well known to frustrate efforts by marketers to gain access to your private data.
But is no less becoming a spy agency in its own right. The fact that they don't sell the info to marketers as directly is beside the point. Although "in-app-advertising" is rapidly becoming a 'big deal' for them too. They control the browser (with very poor security privacy features, they control the maps, they control the store, they aren't much 'better' then google.
These days I think Microsoft is the least evil of the group, and that's saying something, and perhaps that's only because they don't have the marketshare in mobile to leverage the evil.
Since I have to use them, I'm going to use something I like a lot and not have to worry about too much.
And that's fine. But choosing a samsung and the official store is as safe as using an iphone.
If apple was only concerned about security Apple instead of profit lockin they could even officially sanction 3rd party stores like Steam, the HumbleBundle, FSF repos, Amazon, whatever, etc.
In the real world, we have a choice of stores to shop at, and we can leave the security of shopping at stores and buy on ebay and craigslist or from a guy on a blanket on the side of the road.
If you don't want to get ripped off deal with a reputable store. People by and large understand that, and that model works on the internet too.
We don't NEED to be forced to all shop at X and only X to ensure we don't get ripped off.