Larry and Sergey don't work at Google anymore. They're much more laissez-faire, working on special projects across Alphabet. They don't make most of the decisions that effect Google employees, and don't have answers to most of the questions that are asked. That was the entire point of promoting Sundar, after all: so Larry could step away from Google.
And finally, Larry and Sergey being at TGIF's undermines Sundar's authority. He's the one making decisions, and he's where the buck stops, but having the cofounders there creates an uncomfortable dynamic and makes it seem like they have a larger role than they do.
So it's not a matter of "courage" and "accountability" as much as corporate governance and priority changes. There's no drama buried here.