It would be nice to have a nice 4-3 game in a game 7 of a Cup Final, I'm just saying that doesn't generally happen.
The first thing a team will do in a game 7 generally is throw everything they can at neutralizing your superstar player for 3 periods. That's hard to do over a long period of time, but for one game ... you can do it if your players play with a stick up their ass and are vigilant in taking away time and space.
Refs are not going to want to call a lot of penalties in a game 7 either, so that is an auto advantage for the team with the lesser stars. They can get away with more holding and obstruction.
To win those games you need your goalie to make a save that the guy on the other net is not making, even if it's just one more save. If your goalie can hold the other team to 1 goal in a game 7, the longer that happens the better your odds of having a dumb luck break/one of your role players score a garbage goal.
But if the opponent gets up by 1 ... forget it. In a game 7, especially if you're talking now you're well into period 2 ... yeah getting that goal back is going to be near impossible. The opposing team will completely go into a trap shell and every player will play every shift 110% balls to the wall defensive effort to prevent you from getting a second goal. It's not the same game anymore.
Coming back from 2-1 in a game 7 with the clock ticking in period 2 is not a simple task. You might as well be climbing Mount Everest with zero oxygen. It's not easy to get that goal back.