And if you want a phone that works that way, they do exist. Personally I'm happy to offload most of that to one service provider, so I'm happy to use an iPhone. If that changes, I'll look elsewhere. Your mileage may vary.

>No, because you can make your phone work with other service providers. The dependence on the original hardware vendor is artificial.

Yes. But then it wouldn't be a commercial commodity product, it would be more of a build-your-own DIY kit. Would it be as succesful?

>Choice of blacklists, content filters etc. is also orthogonal to the vendor.

Everything is orthogonal to the vendor, even choice of screen or disk.

But most people don't like choice, want something that mostly works as is. And even for those that do the optionally increases the product complexity, maintainance, and error condition space (integrated vs mix-and-match).

Plus, a few modular laptop and mobile phone designs never sold well.