Android on the other hand is developed by thousands of engineers and is a much larger project in terms of monetary investment than Linux. Linux was essentially built by a single guy. Android could never have been built by a single person or even a open-source project. It's too massive.

However complex you think Linux is, its just a kernel and doesn't require a conglomerate to build and maintain for billions of users. Android does, and those developers need to get paid for the massive value they provide.