When Shanny was hired, he said the problem in Toronto is not making a plan it is sticking to it. This is a perfect example, if Leaf fans had their way we would go back to firing our GM every 3 years, forcing them to make win now moves instead of long term moves year after year, even when the team is not good enough to compete.
In his 10 years, he oversaw an entire rebuild top to bottom, off ice and on. Then he also had the pandemic to deal with which yes, every team did as well, but not right after committing 40M to players expecting the cap to go up.
There's also the fact that while yes they were a playoff team, the players themselves were 19-23 years old for most of those years. Yes you can say it was a mistake to pay the players big money without being proven, but I mean the players kind of forced it.
Ultimately, it is on the players not coach, gm, or president. They haven't done what Oilers players did or Avs players and dominated a series. However, they are also top nhl talent and it would be silly to assume you are better without them. He has no choice but to keep going with this team until the wheels fall off.
All it takes is 1 run.