Recency bias is a thing. The voters just love the shiny new toy, especially if they can craft a narrative around it, like Bruno having to take over in such "trying circumstances." Pfffffft...dude got handed one of the most talented and deepest rosters in the entire league, with an extremely solid goalie tandem, and all he had to do was follow the blueprint already put in place by his predecessor. Literally the easiest job in the league. Now that he's actually having to make changes to that blueprint, he's faceplanting hard.
Don't get me wrong, I figure Bruno is a good guy and may one day be a good head coach, but right now he's just an interim guy riding his predecessor's coattails.