(A)lthough he was a elite private school valedictorian, ivy league graduate, and had a very active social media profile, nobody from his past ID'd him. How can that be?

And yet a burger flipper at a McDonald's recognized him?

Good point, why the heck didn't anyone who actually knew him ID him?

Whatever, he was captured alive. There will be a trial. Unless he mysteriously suicides in jail, there's still a lot to play out as global theatre.