Putting a great goalie with a great D also tends to result in an output that's less than the sum of the parts. Can be seen from Nashville and Dallas, goalie doesn't have to cover for an amazing defense, as a result doesn't get as many regular shots against and lets in stinkers because he's out of rhythm after going for 10 minutes without a shot against. In turn the defense is playing really sound two way hockey when they can push more on offense and the goalie could bail them out. Meanwhile Blues (great defense with solid but not amazing goalie) or Bruins (great goalie, above average defense but their top guys were out of their primes and not Pietrangelo/Parayko Norris level players) got the most mileage out of their combo. Hurricanes as well, with great defense/dependable goalie. Capitals the year they won had great goalie and good system defense without big names minus Carlson (who doesn't get much respect defensively) but allowed a lot of shots against because they'd always push the attack and knew Holtby could bail them out on the average shot taken against him.
Not that having a great defense + great goalie is bad, but if Bobrovsky is facing 30-35 shots against a game he probably puts up a Vezina caliber performance, and if the Panthers take advantage of him being back there to press more offensively while defending high danger chances within reason they become a very formidable team. You need two way commitment to win but 5 skaters can't be everywhere at once.