For me, as someone who's watched combat sports since the early 70s, yes, I think Justin Gaethje now knows he is NOT the alpha male in the division.
He also knows (now) that his stamina and grappling are sorely lacking.
In a rudimentary fistfight, sure, Justin Gaethje will always be a danger ...
But my read on his body language, and everything else since he got crushed by Khabib, is that Gaethje's soul has been truly beaten.
In other words, will take a lot more than a "pep talk" to get him back in the game, IMO.