This doesn't make sense to me. The iphone 6 is a flagship phone. It's priced about the same as android flagship phones. Their previous flagship phones remain in the lineup as "budget" options. So they really aren't any more expensive than the phones they are meant to compete against. I suppose you could fault them for not making a current generation budget option, but apple has never done that.
This is a personal preference thing. My brother got an LG G3 for christmas. naturally he's a big android fan all of the sudden (You should note that as flagship phone, the LG G3 is at least as expensive as an iphone 6). Anyway, he was telling me about how his phone was better than mine because of how customizable it was. All I said was "Oh really? Well what have you done to it to customize it then"? He said he had changed the background and lock screen. :\
That's the case with a lot of the customization options in android. The default android skin works so well and looks so good these days that few people would change it significantly. Installing a custom ROM is just as likely to introduce new problems as it is to improve your experience, and it probably voids your warranty in some cases anyway. Apple just went the route of providing something that would work well, and then making sure you can't mess it up. People like to say "They're taking away our FREEDOM man"!, but really you're just as free to jailbreak your iphone and do all sorts of funky shit with it too, a process that is probably easier than installing a custom ROM on an android phone anyway. So what if apple frowns upon jailbreaking. They're just trying to protect their reputation as a company that offers products that work without breeding malware or glitching out on you, something that jailbreaking tends to undermine. This mentality is why apple's shit mostly can be relied on to do what it's supposed to do.
This I agree with you on. Although I suppose an argument can be made for apple not allowing sd cards because they might be used to load unapproved software onto a phone, I really think it's mostly so they can charge exorbitant prices for every successive level of storage space. A lot of the android manufacturers have begun following this practice as well though, so it may not be a difference android fans can point to for very long.
Once you understand that apple really is concerned about everything in their ecosystem working well together this makes more sense. It's why apps for the the various iproducts will often exhibit more polish than their android equivalents. It's why apps with malware are a rarity in the app store. It's why I can often download an app on my nexus 7 2013, have it not do what it's supposed to do, then download the same app on my iphone or ipad and watch it work perfectly. Curating the app store like this is harder, not easier. I'm sure apple would rather not have to do it, but they want their shit to work, and they want to make sure they're getting their cut of all the in-app purchases (don't think I forgot that little aspect).