Nowadays, 40 goals is quite an achievement. It was also quite an achievement in the 1950s and 1960s (and in the 1940s, though rarely done).
Between 1940 and 1960, only twelve 40-goal seasons occurred. The first seven of those were ALL by Maurice Richard (x4) and Gordie Howe (x3) (Gordie also had a 4th). Beliveau (x2), Bathgate, D. Moore, F. Mahovlich, Geoffrion, Hull (x4), and N. Ullman complete the players who achieved it in those years.
Maurice Richard was thus the only hockey player to score 40 goals in a season during the 1940s, and he did it three times (counting 1949-50).
Bobby Hull's 54 were the most anybody had ever scored in a season before expansion, after which Hull pushed that up to 58 (1968-69), and then Phil Esposito destroyed this, going to 71 in 1970-71. That was the most until Gretzky in 1981-82, which has yet to be topped (Gretzky himself came closest in 1983-84).
So, obviously the old days were way different, but consider that there were twelve 40-goal seasons from 1940 to 1960, and in 1992-93 alone twenty-five players scored 40+ goals.
I will say that since I started watching NHL in 1986-ish, I've always felt that 50 goals was the magical number for an elite goal-scorer. It didn't matter if it was 1987, 1997, 2007, or 2017 -- if you hit 50, you were an elite goal-scorer. It's still that way, of course, but 50 is now quite rare.