I'm not naive, but everyone takes the OS source code and platform for granted, and asks, "what else can I get"?
It's obvious that Android has enabled and continues to enable an ecosystem of hardware companies to thrive. These companies have tried repeatedly to build their own software, but with NO commercial success. Imagine a world with an Apple like Android, Google owning the software, closed sourced, walled, yada yada ... That's still a possibility if the ludicrous EU actions on Android don't stop. Google makes about 1/10th the revenue and 1/100th the profit off Android as Apple makes off the iOS product lines.
Android's ecosystem gets a LOT more out of Google than Google gets out of Android
EDIT: Samsung, LG, Huawei, ... they're even relevant in phones because of Google. I doubt it's the other way around. Samsung is SO scared of Google cutting it off that it tries repeatedly with alternate OS-es --> everything from Tizen to windows phones. Nothing sticks