Even setting the McKinsey stuff aside, Americans are just done with neoliberalism, and unfortunately that's what Pete Buttigieg represents and hasn't repudiated. Nor could he ever convincingly repudiate it, at this point, because he's way too committed to it. He's a younger, male, Elizabeth Warren. America doesn't want that anymore, if they ever did.
AOC became the defacto leader of the party for many reasons, but one of the biggest reasons is that she doesn't campaign like a neoliberal. Her policies are socialist-adjacent, which used to be disqualifying but now is an asset. People, not just young people, want socialism. They reward socialism at the polls. And they punish neoliberals, like the asshats who run the DNC who can't even allow a Palestinian to be heard for five fucking minutes, with apathy and third party votes.
I like Pete, personally, and I know he could do the job and do it well, even if he and I don't see eye to eye on policy. But nominating him is like bringing caviar to a honky tonk. Just give the people what they want already, for the love of god.