Personally, I think it's the player that defines a decade. I like to think there is up to 2 F's but usually one, and up to 1 D. The point totals follow but don't define.
80's: Gretzky, Lemieux
90s: Jagr, Lidstrom
00's: Crosby, Ovie
10's: McDavid, not yet but maybe one day Makar
20's: TBD with a placeholder for Dupont but we'll see
The players that are just heads and shoulders above even their all star peers, and they're there perennially, and at the end of their careers people are debating whether they're the best ever at X, where X is something important like the entire position or goal scoring or whatever. Especially the case if they redefine how the game is played or seen.