From what I've read in other stories etc, the coach doesn't do a lot of addressing the team in the intermission. I don't think Bowness would've said "one more bad shift and you're benched", especially given that he benched the entire line and not just Scheifele, indicating he wasn't happy with the performance of all 3 players.
To be clear here, I don't believe, and I don't think Reynolds believes, that Scheifele is taking this as "I'm too good to be benched". Maybe he is, but I don't think so. I think he doesn't respond to that type of motivation and instead gets in his head about it - I'm sure we all know someone who withdraws when criticized instead of saying they're going to go prove them wrong.
As above, I don't believe it's not being smart enough to understand why they were benched but the response to it.
Increasingly in the NHL you don't need an elite goaltender to win, you just need someone competent enough, as long as you play the right way in front of him. Kuemper isn't a world beater, Colorado was just too good. Unfortunately the Jets don't play the right way in front of Hellebuyck so they need him.