Agreed, very few teams change their GMs coming off a record setting 105 point & 100 year franchise best mark for wins and points in a season.
The Leafs were coming off of 40 & 49 win seasons or [89 win total] in 164 games (2 seasons prior) and now Dubas has recorded +11 win improvement in his first 176 games [in +14 extra games]
If however you compare past and present GMs to the same 164 game mark matching games played and apples to apples.
Lou Lam
89 wins in his last 164 games (2016-17 & 2017-18)
&
Dubas in his first/next 164 games 2018-19 (82 games & 46 wins) + 2019-20 (70 games & 36 wins) + (1st 12 X games of 2020-21 & 9 wins) =
91 wins in 164 games.
The Leafs saw a
marginal +2 win improvement in the 164 games prior to the GM change, compared to the post GM change.
This is what you would expect at minimum where the table is already been set and handing over a 100+ point team.
PS. 1 X GM inherited a last over place overall team with 29 wins, and the other inherited a franchise best mark team with 49 wins as their starting points.