I guess Carrier app store in USA might be allowing to purchase and install through their billing which hurt Google.Mi too I imagine. So two of the largest Android companies are shipping their phones with their own stores already.
the article talks about wireless carriers. at one point of time iirc verizon had their own app store. i assume att and tmobile also had their own stores. not sure how that is even a good thing. especially considering user can install a third party app store at any time.