I'd just like to point out that both Tampa and the Isles missed the playoffs by 1 point last year. Imagine the outrage if Kucherov or Tavares had been "rested" for any games, not needed to recover from injury.
Also of note, the difference between 1st in the Atlantic division and missing the playoffs was 9 points - not a big deal. But between 2nd in the Atlantic and missing the playoffs was 4 points. Boston and Toronto were 1 point ahead of Tampa and the Islanders for the last division spot and last wildcard spot in the East.
Or if you look at 2016, where Boston didn't make the playoffs because of a tiebreaker going to Detroit.
I wouldn't say there is anything resembling league parity, given that the Rangers 102 points last season was good for 1st wildcard as a Metropolitan team, but 1 point back on Montreal's 103 point 1st place finish in the Atlantic division. What about Calgary and Nashville each finishing with 94 points for the west wildcards, 7 points ahead of Winnipeg and 8 points ahead of LA? Those point totals are non-playoff finishes in the Eastern conference.
With things that close at the bottom, they can't afford to rest players at all. And the teams above them can't afford to lose points either, or they risk their own spot in the playoffs until the very end of the season after they clinch a spot.