Last I heard you can ship Android without any Google components, you just can't call it Android.
The real issue is popular apps like Snapchat and Maps that require Play Services. So manufacturers are never going to abandon the Goog for fear of their customers not being able to run the latest fad.
You mean AOSP, Android has a completely different meaning and expectations in general use.
Apart from apps that need the Play Services, lack of the Play Store is the biggest issue with shipping AOSP. That's why they forcibly bundle it with all other Google apps and default as Google search.
Chipset and device manufacturers, and carriers, hold all the cards though. Samsung and Amazon could conspire almost overnight to bring about a real contender and, failing something bold like that, Windows Phone has always been an option.
The real issue is popular apps like Snapchat and Maps that require Play Services. So manufacturers are never going to abandon the Goog for fear of their customers not being able to run the latest fad.