Every single team in the league has moments where they look like they don't care at all, the Avs are no different. The weaker the team the more likely you are to see garbage play and "mental" mistakes which I just consider a product of a average roster.
The Avs are different in that they have more of those moments. That's what separates playoff teams from non playoff teams.
A teams roster makeup is not the reason for mistakes and a lack of effort. These things are preventable by any NHL roster.
Mistakes are the bigger issue than a lack of effort. I think the effort has been there most of the season until lately, where they've come out flat a few times when they needed to play like they were pissed off at their previous performances.
The preventable mistakes have been there from the beginning of the season though. Turnovers in the D zone, defenseman getting puck focused or losing their assignment, not bearing down on your chances, passes that are off the mark, PK letting passes go through the box all year.
These things happen too often for this team, and they're things even an average roster can weed out. It doesn't have to do with their talent or ability. They're capable of being better but they're not.
That's why pretty much everyone outside the top line and Soda has had a disappointing season to their standards. They've all underperformed, and the coaching staff for various reasons hasn't been able to correct course.