You're missing the forest for the trees. PK is not easy minutes, its tough minutes and he still has the ability to hit PPG stats. Very few players produce every game in the playoffs, McDavid didn't produce a point in Game 6 or 7, in the most important games of his career, should he get the same vitriol as Marner? As you say he disappeared.
Does he deserve blame for the 1 - 8 record, sure he does but not alone, but it seems like a lot of poster here blame him and only him. the story goes, we are not trading Matty, Willie gets a pass because we just signed him, great logic there.... JT well JT is old and who would want him, another construct to build the only possible person that we can trade, is Mitch narrative.
Maybe the coach was a f-ing moron that has no clue how to manage the playoff game? Maybe the guy who refuses to adjust during the playoffs is more of the reason why we are 1 -8? Maybe the reason why our offence dry's up every playoff series is because our coach is getting out coached... nah not possible ...