I don't think "HOW" doesn't matter. It's a matter of taste, but I think that having the OS handle important stuffs out of the box like WP does is really important.
I see it like this: WP "as is" has a lot more in its shelves than iOS and Android. The first has Siri (what else ??) and the latter has google apps. WP has (or will have) all the Bing goodies, plus Nokia services and sort of webOS like synergy ecosystem (integrated connection with Windows Live, Google Talk etc... and other services that you can setup without third party apps).
Those are services that other OS's can only handle with third parties, and I know for sure that most of non-geek smartphone owners *never* buy/dl apps ! Whenever I ask around me to smartphone people who doesn't care much about new techs, they always say that 1) they don't what apps are good for or/and 2) apps does not interest them.
Most people use only what the OS can do by itself. They don't spend hours trying to find an app that *might* interest them.
Sure, for those people Siri is a good service to play with, but remember that WP8 will bring a *lot* of features that can compete in better ways I think. Not as ludic as Siri, but really usefull and easy to use.
So what is so unique with WP? Sure, the social media integration is a good idea, but if you use Facebook or Twitter you still have to use the "third party"-apps for most tasks. Two interfaces for the same service is IMHO not innovative.
And Facebook comes preinstalled on almost every Android-phone, and most OEMs have some sort of integration of social medias in the UI.
You can setup Windows Live sync, Google Talk etc. without apps on Android too, just to take your examples. Google Maps is superior to Nokia Maps, Google search instead of Bing. WP has Office and Android has by far the best YouTube integration.
No, WP is not unique when it comes to features out of the box, however I don't think of that as a problem. It sounds like you have missed the whole "app revolution". 10 year old kids know how to download the latest games. People who don't even know what OS their phone has are using Facebook, Twitter, Youtube etc.
"Most people use only what the OS can do by itself". If you were right WP would be as poor as the others, fortunately you are so wrong.