Re: If you build it will they come?
You're not quite there with your analysis. As in miles off.
This isn't about better/worse products and competing with them. This is about Google holding a near-monopoly on a licenceable, practical phone operating system and a monopoly on services AND a range of apps. A manufacturer cannot chose Android, Play store, Google location services, Firefox, Here Maps and Bing as their default configuration on any device they sell, because then NO device they sell may use Google location services or any other component of the Play store. By contract.
No potential competing company can reasonably make many services or apps and distribute them as default installs on new phones, since the phone manufacturers then cannot use any of the Play store services and bits on any phone they make.
Because of Google's monopoly position and the barrier to entry*, the contract is anti-competitive and illegal under EU rules (and probably NZ, AU, CA and a great many other jurisdictions).
* The barriers to entry require replacing the Play store, all associated services (huge task), funding the back-end delivery of all services and seeding the new store with critical apps (i.e. pay for app ports and ongoing updates). There's probably stuff missing from that short list. And doing this while maintaining a revenue stream WITHOUT phones until it is up and running properly.