They won because of prospects. Every year they had amazing 1st and 2nd lines but crap 3rd and 4th lines because they traded their depth and couldn't afford to get good pluggers.
This year they had Dumoulin step up along the back line and several guys step up on the 3rd and 4th lines, giving them quality depth for the first time in forever.
Plus, most obviously, Matt Murray.
The Pens' best trades were equivalent to "Pirates trade Justin Wilson for Francisco Cervelli". You just shrug your shoulders and go about your business for the day because it doesn't move the needle.
Those trades didn't matter back then, why go out of your way to try to make them matter now?
It's like the people who tried to give AJ Burnett credit for the Pirates turnaround or Slice credit for Pitt basketball's success. Or then called AJ Burnett a clubhouse cancer because he got mad about not starting a playoff game (the team then went on to win 98 games with "zOMG clubhouse cancer AJ Burnett" on the roster 2 years later).
It's all just dumb drivel. For as much as sports fans like to throw out the "wow, man up and don't be a woman" card, sports writers are literally just writing romantic storylines for men to read and digest. They're merely playing on emotions, not facts or reality.
Don't try to make a story out of something that doesn't require one. Sports are, after all, taking place in the real world. There is no greater meaning to them, despite the media's insistence on sensationalizing everything. Some guys win, some guys lose, there's a bunch of luck involved, and at the end of the day you just do what you can to strip away the luck aspect and move forward in your decision making. That's it. That's sports. If you make it more than that, you're overthinking it and being way too emotional about things.