If defence is everything you don't think losing our best defensive player for 3 games was a factor?
Defense isn't everything its just the most prominent thing to that brings you consistent success.
Losing Muzzin doesn't explain why the Leafs almost got shutout in 3 of the 5 games in the series.
All you have to do is look at the NHL standings where so many falsely focus on
Goals For and driven by offensive stars and think Offense wins and then look at the results and see all the Matthews, Tavares, McDavid, Draisaitl, Crosby, Malkin, Panarin (top points leaders) etc etc on the sidelines while many of the teams in
Goals Against best category move on to qualify for the playoffs.
Its how you explain Columbus, Islanders, Arizona, Montreal, Carolina, Calgary all with bottom 15 offenses but all one thing in common all top 15 in Goals Against.
Here are the NHL's top 10 best defenses (least goals against on the season) with bolded already qualified for playoffs without play-in.
1).
Boston Bruins
2).
Dallas Stars
3). Columbus Blue Jackets
4). Arizona Coyotes
5).
Colorado Avalanche
6).
St. Louis Blues
7). Carolina Hurricanes
8). New York Islanders
9).
Tampa Bay Lightning
10).
Philadelphia Flyers
Perfect
10 for 10 for qualifying and playing in this years playoffs.