People don't understand what's at stake, just ask around. People buy iPhones because they're "nice" and because their best friend has got one and he/she's showing off how expensive it was.
I doubt that's the "why they keep buying iPhones" when other factors include wealth signalling, social fit-in and SMS bubble color fashion.
If they had a problem with the walled garden they wouldn't buy it. Say "walled garden" to the average iPhone owner and they'll say "So? That's a good thing".
The average iphone owner (and average android owner) would ask why you are asking them about their backyard.