In theory it would energize extraverts. I get the impression this is taking Jung's idea of "psychic energy" a bit too literally, but social interaction should at least be less tiring for extraverts than introverts. Besides that, introverts brains are running too... just not in ways that are concerned with interacting with other people.

I'm inclined to agree with the account at the end of the story. Extraverts have a strong need for belonging. If everyone around them is tired, then I wouldn't be surprised if they "became" tired too to be one with the team.