The fly in the ointment for many of those blaming Lalonde for the failure to make the playoffs and thus vulnerable now, is their mistaken belief the team is skilled enough to justify playoff expectations. They're not. They vastly outperformed their skill level last season and were only close to making the playoffs because of PP effectiveness, third-period comebacks, a terrible Metro Division and dysfunctional teams in their own Division.
What do skilled teams do? They create quality scoring chances. The Wings last season, according to Natural Stat Trick, tied with Chicago for the league's fewest High Danger Chances 5v5. That's not a one-year blip. The year before they had the second-fewest, ahead of only Chicago. Their differential in High Danger chances created and given up last season (minus-140) was in the bottom 10 in the league, It was minus-168 the previous season. There are exceptions, but you generally need to get fairly close to a zero differential to have a realistic shot of making the playoffs. Last season 14 of 16 teams had a positive differential.
The Wings lacked talent in goal (the second-worst Save Pct on High Danger chances); their D lacked ability to initiate/execute controlled zone exits, usually a necessary precursor to controlled zone entries; too many of their forwards lacked puck possession skill They made up some of the talent deficit by outscoring all but five teams on the PP, just one less goal than the Oilers, who to me at least seemed more than one goal better with the man-advantage over 82 games. They made up some of the talent deficit with late-game heroics. You don't have as many wins when trailing after two periods as the Wings had (league-leading 11) or league-best third-period comebacks overall (14 IIRC) unless there is a high level of collective faith it can be done and the shift after shift work rate to make it happen. Good special teams and the will and work rate to win a high number of games they easily could have lost -- in some people's minds, that might indicate good coaching and players buying into what a coach is selling.
What teams are most susceptible to long losing streaks? Bad teams. Teams with not enough talent to make up for bad goaltending or the absence of one of their few good players. With not enough talent to eke out a win when their effort/execution level predictably drops for X number of games. Lalonde's job is vulnerable because all coaches are vulnerable, especially those with bad, mediocre or overrated rosters. A long losing streak for any of those teams could result in the coach being fired.
They might sneak into the playoffs next season with a lot of help and more of the same things that got them close last season, but they're a long way from coaching quality being the primary reason for coming up short. Last season, if you look at the big picture of talent disparity rather than getting tangled up in the weeds of immediate post-game and post-season complaints, coaching quality helped keep them in it.