I'll never understand the "the old days was a six-team, all-Canadian League so everything was easier than now!" argument.
Let's break this down:
-- It's generally harder to score (or succeed) against higher-level players than against average-level players. Agreed?
-- There are something like 400 Canadian NHL players today, right?
-- There were something like 110 Canadian NHL players in the early-1960s, right?
For the NHL of today to equate the "Canadian level of talent" of the 1943-1967 era, we'd have to get rid of all European and most American players, yes, but then we'd also have to get rid of the less elite 72% of today's Canadian players, who would no longer be good enough to play.
So, now, there'd be six NHL teams with all Canadian players, and we'd throw Ovechkin in there as the only European. Now, I ask you: If 72% of today's Canadian players wouldn't be good enough to make this League, would Ovechkin have an easier or a harder time scoring? It might be the same, but it certainly wouldn't be easier.
Ovechkin's PPG last season was 0.985 per game, so in this all-Canadian League (if his scoring levels stayed the same) he'd be around 9th in NHL scoring.
I ranked the 183 Canadian NHL forwards who played (min. 20 games) last season by PPG. There were 183 such. So, in this all-Canadian proposed League, 132 of these current NHL forwards wouldn't be good enough to play. These include players like Ryan Getzlaf, Zach Kassian, Jamie Benn, James Neal, Jake DeBrusk, Jeff Carter, Joe Thornton, etc. (Yes, I'm aware some of these guys bring things besides just scoring, but you get my point.) These kinds of players, in 2019-20, were comparatively all minor-Leaguers when Bobby Hull was young and hitting his prime.
A player like Tom Wilson (today a 1st liner on Ovechkin's team) would likely be a 4th-liner in an all-Canadian six-team NHL today. Guys like Josh Bailey and Jordan Eberle, if they made the cut, would be 4th-liners. So, Ovechkin would have higher-talented linemates to play with, but likely some of them would be goal-scorers and would take some of his PP-time away.
And obviously, the goes for defencemen, too. Ovechkin would be facing only the 30-or-so best Canadian defencemen in the NHL today. Basically, the bottom-two or three D-men on each NHL team now wouldn't be good enough to play.
It would not be easier to dominate this League.