With things like Doze, the only thing that can wake the device is a push message FROM GOOGLE.

That doesn't sound open in the least.

"The underlying theme connecting these libraries is that they're clients for Google's proprietary protocols."

Protocols which are quite difficult to change out. If you're a person who doesn't want to use Google's maps, you're SOL for most applications that show maps within the app, as most of them are using Google, because it's easy. Whereas if the location services were just a system plugin, the user could choose the mapping data provider they wished, and the app would just receive map data and continue as normal.