Android was never open. Its security model / the permission system is anticompetitive and the user is a third class citizen.

Google can do everything as they control the system - this gives full innovation capabilities. Then there are vendors which are restricted by Google via CDD (checked by CTS/VTS), they might add "privileged apps" but they can't touch what Google does on the system..

And only then there are regular developers/users, apps which they can install have very limited capabilities, they can't extend the system beyond a limited set of APIs that Google allows them to use.

This limits third party innovation already, but Google constantly makes it worse by restricting third party app capabilities even further under the guise of "security"..