Is everyone here under 30 or just completely off their rocker? Sure, conditioning is better now. People are bigger and faster. They have better equipment. They are a product of the time. But everyone here keeps assuming you "drop" Ovi into the 80s and he'll dominate. Are we also taking away his diet and workout regimen? His equipment? All of these things would have a drastic impact on the way anyone would play the game. Ovechkin is one of the most dominant goal scorers in the history of the game. Is he the greatest of all time? Maybe, but it's unclear and anyone stating he is the GOAT is obviously biased in one way or another.
The only way to truly determine how effective he is compared to guys like Mario, Gretzky, and Jagr, would be to have him play under the same factors as the aforementioned players. To state that he is the greatest because he'd dominate the players of the 80s is a straw man argument and a fallacy. There are so many factors that would play into the way he dominated. Because you're not going to get 2018 fitness levels and equipment if he were playing in the 80s. Neither would it be fair to drop a player with such a large advantage into that pool of players.
Give the average man of the 1985 NHL season the same workout routines, dieting, 24/7 nutritional coaches, and equipment worn by the guys today and many of them would be on the level of the average 2018 NHL player. Vice versa for the average player of today.
To sum up my rant. We never will really know. Can't we just enjoy all these players for who they are instead of trying to see who would pee highest on the wall?