Isn't this how any meeting is supposed to be run?
I can't tell you how much I hate the meetings I have to go that devolve into time wasting because there's no agenda etc.
But even if they do, odds are they're going to run into problems of just trying to schedule meetings in the first place (hence regular, weekly meetings even if there's nothing to discuss), people unprepared even if an agenda is provided, and not having enough political clout to make sure that the everyone who needs to be there actually is or to shut someone up who's wasting time.
Mayer is in a position where she's not handicapped with those issues. Most executives wouldn't be either. The question would be are the rest of the meetings at Google this efficient?