Coaches (not named Blashill) typically don't survive two consecutive seasons like this, UNLESS it's early in the rebuild (it's really not for us) like the beginning of it or they're very poorly run and don't know what the hell they're doing like Ottawa.
And I'm only using Ottawa because this is DJ Smith's third full season there and I'm not sure if he'll be back or not and Ottawa doesn't exactly have a reputation for keeping coaches too long. They actually went through more than most teams in the 10 year span before DJ Smith, but I could see them staying the course, but they're so poorly run you can't take them seriously.
It's actually VERY RARE for a head coach in the NHL to survive three straight non-playoffs years, no matter what the status of the team is. Ruff has only had 2 so far though.
Outside of TRASH in Detroit, I don't think there is another currently going for a fourth season after 3 consecutive playoff misses.
And honestly, I don't wanna hear about Yzerman. Yzerman (as of this second, maybe not a in a few years from) is considered a good GM because of what he did in Tampa. It's too early to really say he's not doing a good job in Detroit, but the Blashill extension last year (like, he actually extended him, not just kept him leftover from Holland) was a bit suspect.