I’m guessing this plays a bigger part than comments here give credit for. Pichai isn’t pitching anyone on anything of consequence to him at this commencement. He is, broadly speaking, flattering his ego.
If you stand in front of a room full of people, about to give a speech, you already know that you aren't going to reach 100% of the people present. Moving the floor to 90% hardly matters at all, and the fact that the minority wasn't able to mobilize the majority would be my takeaway.
Beyond that why do any of these guys give speeches? They do it to raise their profile, to polish their ego, to promote recruitment or their ideals, and of course because they genuinely believe they have something to offer.