If Lucas hadn't had the (absurd?) trademark on "droid" I think "Droid OS" would have been easier to market. Though, even then, there were other issues.

The move to drop "Android" makes sense. "Google" is a name that people generally trust (despite the efforts of MS's petty 'Scroogled' campaign).

"Android", on the other hand, has come to represent a disjointed conglomeration of smartphones. The OS versions are inconsistent between phones and have names that give no indication of chronology. Reach into a bag of current Android phones and pull out two at random--you have no idea what to expect. Certainly Microsoft deliberately avoided this specific pitfall in their design of Windows Phone 8.

Motorola jumping early into the fray with "Droid" phones running "Android" likely added confusion.