To a certain extent. But the elite guys still produce relatively close to their regular season averages.
Crosby:
Regular season - 38 g, 102 pts
Playoffs - 31 g, 92 pts
Ovechkin:
Regular - 50 g, 89 pts
Playoffs - 40 g, 79 pts
Kane:
Regular - 31 g, 85 pts
Playoffs - 28 g, 75 pts
Matthews:
Regular - 51 g, 92 pts
Playoffs - 36 g, 72 pts
In the first three cases, the points drop was around 10 points below their regular season per 82 career average. Matthews drops by a whopping 20 points lower than his regular season average. And that's not taking into account that the first three have suffered from the "production goes down when the player reaches 30+ years old" thing. Crosby, for instance, was averaging over 100 points in the playoffs prior to the last 4 or 5 playoff runs when he hit 30 years old.
Not to mention, in term of his area of strength (goal scoring) he drops from being a 51 goal scorer in the regular season to a 36 goal scorer. Ovechkin still maintains a 40+ average despite the fact the last couple of runs at age 34 and 35 hurt his average (only 3 goals in 11 games). Crosby, who is more of a playmaker than goal scorer, only sees a drop from 38 goals to 31.
That's the problem. Matthews, in comparison to other elites, sees arguably the biggest drop in production come playoff time.