No it wouldn't. You're seriously underestimating the resources and money it would take to even attempt that. Google has an army of Android developers working on

No it wouldn't. You're seriously underestimating the resources and money it would take to even attempt that. Google has an army of Android developers working on all aspects of the OS from design, security, tooling, architecture, infrastructure, features, bug fixes, etc. Others have tried and spectacularly failed because it's hard. Besides, you'll never have the developer support.