Play services are not necessary to run correctly and effectively android. Notifications can also not be handled by Google (unified push exists), payment platform can also not be google, curve is there.webview: I know at least two other webviewers that can be used, phone projection through USB to an monitor is now within AOSP, or you meant android auto and good news: there is now a way to get it outside of Google and degoogled roms are starting to push it forward.