Few teams possess the puck more than the Sharks and Hurricanes, but plenty of teams score more.
According to Puck on Net, when adjusting for score and venue, San Jose and Carolina are in the top four of both major possession metrics (corsi and fenwick). They're 11th and first in the league, respectively, in shots per game, and 29th and 30th in shots allowed.
The Hurricanes and Sharks are also first (54.43 percent) and 13th (50.96 percent) in five-on-five scoring chance percentage, per Natural Stat Trick. Despite this, neither team can finish: Carolina (7.53 percent) is 30th and San Jose is 29th (7.74 percent) in all situations, according to Corsica Hockey.
Unsurprisingly, both teams are in the bottom five of goals for per game this season. Yet, San Jose's holding on to the last wild card spot in the Western Conference, with at least a game in hand on the three teams chasing them (Calgary, Anaheim, Minnesota), and on the two teams they're chasing in the Pacific (Vegas, Vancouver).
Carolina, on the other hand, is six points out of the last wild card spot in the East, albeit with three games in hand. Goaltending, particularly on the penalty kill, has been the difference.
Across all situations, the Hurricanes have the league's 23rd-best save percentage (.900), while the Sharks are second-best (.922). That gap is driven by a shorthanded save percentage disparity, as only half a percentage point separates San Jose (.925) and Carolina (.920) at even strength, per Corsica.
The Sharks have the league's second-best penalty kill save percentage (.917), while the Hurricanes have the third-worst (.826). If Carolina had gotten San Jose's shorthanded goaltending this season, they'd have allowed about eight fewer goals.
Excluding shootouts, the Hurricanes' goal-differential is minus-seven.
The five-on-five difference, assuming they got the same goaltending as the Sharks, is approximately three goals. That's on a much larger sample size (518 more shots) than the penalty kill.
That shorthanded difference can't entirely be explained by each team's respective defense. San Jose allows nearly five fewer scoring chances per 60 minutes on the penalty kill than Carolina, but the Hurricanes allow far fewer shots (50.4 shots against/60) than the Sharks do (59.7).
Taken as a whole, this demonstrates that the margins truly matter for teams struggling to score. The Sharks have gotten better goaltending on the penalty kill, if not necessarily a better defensive performance than the Hurricanes, and find themselves on the right side of the playoff bubble.
If they start to falter shorthanded, however, it's easy to envision them in the same position as Carolina: on the outside looking in.