Possible, sure. But very few interested people are unaware that Waymo = Google = Alphabet in every sense except a technical legalistic one. I don't really think hiding the Google brand's involvement is of the sort of significance of value to justify the whole Alphabet move.

A theory of my own based on this read: A lot of questions Larry Page was asked were below "his level". Compensation, policy, etc. But presumably, as the CEO of the company when this issue started, he is deposed on it. Maybe with a higher level of vertical structure, Google and 'other bets' legal concerns will go up to the level of that subsidiary's CEO and no further. Or to say otherwise, just that creating the additional level of obfuscation moves Larry and Sergey further from being involved in day-to-day operations, which at Google's size is considerable and presumably take up a significant amount of time to be involved with.