They might not quite be on Tampa or Washington's level, but at the same time you don't think a team with the offensive depth Toronto has (essentially two first lines), plus a top 10 goalie and good offense from the blueline, shouldn't be expected to get out of the first round at least one time in the past couple of seasons?
Toronto's consistently been referred to as a Top 10 team the past couple of seasons, and not just by overzealous Leaf fans. And I'd say, based on *talent alone*, that's accurate. You don't think that a Top 10 team is underachieving if it can't get out of the 1st round?
At what point would you consider them to have underachieved? Losing in the first round this coming season? Two seasons more? Five?
Yes a top 10 team in the league SHOULD win a first round, but a top 10 team in the league should also not be playing a top 4 team in the league.
Look at the Leafs opponents
2016-17
Toronto 8th East 14th league
Washington 1st East 1st league
2017-2018
Toronto 4th East 7th League
Boston 2nd East 4th League
2018-2019
Toronto 5th East 7th League
Boston 2nd East 3rd League
2019-2020
Toronto 8th East 13th League
Columbus 9th East 14th League
So its not underachieving if they are forced to match up against true contenders due to the divisional playoff seeding. In the conference format theyd be playing much weaker opponents in the 1st round and your argument would hold some merit.
This season they underachieved as a whole, but in the playoffs they lost to a team with almost an identical record. Disappointing? Yes, but it wasnt some great unexpected tragedy.