If this is the case then it looks Android is more closed than a Windows PC where it would be trivial for a developer to create such a service without the platform owner's permission. How is Android more open than Windows again?
Windows (desktop) is more open in the sense that the platform has fewer constraints on what the user can do by default. Android is more open in the sense that most of the source code is available. These points are not exclusive and do not conflict with each other. It's possible to have a very "hackable" platform without any source code at all - if there is enough interest in RE - and also a very limited platform of which all the source is available, but crypographic signing and other measures get in the way of being able to modify the software.
Windows (phone) is far less open though, and in general this has been the case with mobile devices.
But Windows (desktop) is slowly getting more locked-down too, as a consequence of the "war on general purpose computing".
Windows (desktop) is more open in the sense that the platform has fewer constraints on what the user can do by default. Android is more open in the sense that most of the source code is available. These points are not exclusive and do not conflict with each other. It's possible to have a very "hackable" platform without any source code at all - if there is enough interest in RE - and also a very limited platform of which all the source is available, but crypographic signing and other measures get in the way of being able to modify the software.
Windows (phone) is far less open though, and in general this has been the case with mobile devices.
But Windows (desktop) is slowly getting more locked-down too, as a consequence of the "war on general purpose computing".