I just listened to a podcast where this guy said he had read a book of Bobby Hull and Hull was reminiscing his playing days and how back then goalies didn't have much of a face mask -- if any -- and so he had a habit of aiming a couple shots at goalies head in the beginning of games so that they became timid and then when later on in the game Hull again came ready to shoot the goalie was like hell no not this again and then Hull just shot in the bottom corner and "it went on every time". Now of course this story is anecdotal by nature and some of the goalies back then were absolute sickos in terms of how brave and fearless they were but one kinda gets a sense that skaters were in an advantageous position against the goalies compared to hockey from something like late 1970s and on. Not that it takes away from the domination of peers that Hull did...
I think this dynamic generally tends to balance out, as the "arms race" of improvements to goalies and shooters stays pretty even. At one time goalies had no masks and their skates/padding practically forced them into the old-school standup style, but then again the shooters were using flat-bladed wooden sticks and were moving much more slowly on tube skates. Then the shooters added curves to their blades, so the goalies added masks. The goalies upgraded to modern materials and butterfly-enabling pads, at around the same time shooters started using composite sticks. The rulebook changed to encourage a faster and more open game, so teams started looking for huge goalies who could play the percentages. And so on and so forth into the future.
I think you're right that there was an inflection point in the early-to-mid-1960s where shooters started developing some tricks to upset that balance. Curved blades were the big one. The funny thing, though, is that the same period of time was marked by
lower scoring, not higher. 1964 had about the same leaguewide GAA as 2001. That was the same time that players were adopting curved blades and figuring out how to use them.
Hull had a specific advantage because his shot was just so damn heavy. He was an athletic specimen and could rip slap shots at a modern speed with a wooden stick, while in full skating flight. Even today, a guy like that could come along and shoot at goalies' heads off the rush and they would not be too happy about it. Prior to goalie masks, forget about it. I'm not sure how much we can "adjust" his scoring to account for this, considering it was a valid part of his skill set which would somewhat translate to the present, but it might be fair to say that his winning the goalscoring race by 50% doesn't quite translate 1:1 into modern results. Someone would have to be quite a bit better than Hull to score 75 goals while the nearest competitor scored 50 in the modern league. Ovechkin never came anywhere close to that kind of statistical separation, and they resemble each other so much that it's valid to ask whether Hull's peak goalscoring numbers are contextually inflated similar to e.g. peak Gretzky's.