That's what I figured they would do with Motorola, especially with the move to Alphabet. On the other hand, if it's under another brand name people may not associate it with "first party". When the Nexus line came out, one of the big selling features was "Android straight from Google themselves". If it was from Motorola, it'd be "Android straight from Google themselves because Google owns Motorola so hopefully their internal corporate structure means the two divisions have a close working relationship otherwise what's the point".