Some forget that to win a game, you need to put the puck in their net, not just stop them from scoring. Forwards that can score will always be the #1 players on any team IMO, followed by a #1 shutdown/transitioning D.
I disagree. Obviously you need a strong balance of both, but having just a good forward group will limit your scoring. This chart, courtesy of Episkey:
...shows IMO a trend whereby, teams whose D are more likely to have a point on a goal, score more total goals, regardless of how well-regarded their forwards are. It makes sense, decent forwards are going to score goals if they get a chance whether it's banging in a rebound or being on the ice when a point shot hits your shin pads and bounces in. Teams whose defense are contributing strongly are going to have extra goals.
Having a good D (specifically top 4 with tight gaps, strong outlets, and actual goal scoring skills) with a mobile puck moving 3rd pair gives you a better chance. Having a good forward group doesn't ensure anything.
D are not about stopping the puck from getting in the net, that is the goaltender's job.
D are about making sure the forwards can attack quickly and often, however good they are. They're about giving a 4th and 5th option on the ice to score a goal, helping fool the opponent.
It's easier to live with Vladimir Tarasenko taking 8 shots and getting his goal, than it is to live with Oliver Ekman-Larsson springing a 4th liner on a breakaway who goes top shelf on your goalie.