People definitely do not always come out with their product of choice everyday, but whatever was pushed to them by the "handy sales person" that pushes the product that pays the highest spiff that week.
Case in point: My friend's father in law came home one day with a Galaxy S4 because he was told by the Verizon sales guy that it was better than the iPhone because it had twice the battery life of the iPhone 5 when in fact it's the other way around.
Bingo. The carrier stores push Android phones because their profit is higher, and Android allows the carriers to go back to the bad old days of making deals with hardware manufacturers to put software on the devices that users don't want, and can't take off without rooting the phone.
Nothing would make the carriers happier than for the iPhone to just disappear from the face of the earth. You might say, "But they sell so many iPhones. Why would they want them to go away?" Because if the iPhone were gone they would be able to sell more Android at a higher profit, and continue to push us back to the bad old days. They only sell iPhones because their competitors sell them.
It's sort of like selling liquor on Sundays. In my state there were blue laws that outlawed liquor sales on Sundays. It took many years after the ridiculousness of those laws were recognized, and people started pushing for their repeal before it finally happened. You want to know the biggest lobby to keep the laws in place? The liquor store lobby. Why? Because they made plenty of money on 6 days a week, and didn't want to be open on Sundays. But they knew that once the law was changed and the market was available their competitors would open, and they would have to do the same, or risk losing sales.
Same thing is happening now with car dealerships. There have been pushes in our state legislature to make selling cars two days a weekend legal. The car dealer lobby is the biggest opponent.
The point to all of this is that Verizon, AT&T, T-Mobile, Best Buy, etc. would love it if the iPhone were not available to you and me, because they don't make as much money on it at sale, and they know that Apple is not going to give them the same control over the handset that Android manufacturers will.
So complain about the "walled garden" all you want. I am happy that Apple is working hard to keep a consistent experience for me. I don't need them to protect me from myself. I can make my own decisions, and I do so with my eyes wide open about Apple's practices and policies. I want and need Apple on that wall to protect me from the cell carriers.
