In the mid-1950s there were 18 top-line forwards in the entire league. A couple of them very good players, but come on now.
Yes, there were jobs for about 55 forwards in the pros between 1942 and 1967. Today, there are jobs for 372. So, the 1950s' era, today, would be like if there were about 14 teams in the NHL, instead of 31. Half of today's players would be in the minors. Every NHL team would have near-superstar like top lines, and teams would play one another a lot more often, meaning more checking and tougher, playoff-like games. It would be harder to score than now.
And if I understand the implied sarcasm of your post, your point seems to be that a larger NHL would make it harder for 1940s-to-mid-1960s' era players to be stars. Fortunately, this theory can be completely dismissed by a mountain of tangible historical evidence. For example:
- Jean Beliveau, aged 23, six-team NHL:
1.04 PPG
- Jean Beliveau, aged 39, fourteen-team NHL:
1.09 PPG
- Gordie Howe, aged 18, six-team NHL:
0.38 PPG
- Gordie Howe, aged 22-23, six-team NHL:
1.23 PPG
- Gordie Howe, aged 40, twelve-team NHL:
1.36 PPG
- Gordie Howe, aged 51, twenty-one team NHL:
0.51 PPG
- Bobby Hull, aged 19, six-team NHL:
0.67 PPG
- Bobby Hull, aged 23, six-team NHL:
1.20 PPG
- Bobby Hull, aged 33, fourteen-team NHL:
1.19 PPG
Bobby Hull, aged 41, twenty-one team NHL:
- 0.63 PPG
- Dave Keon, aged 22, six-team NHL:
0.82 PPG
- Dave Keon, aged 39, twenty-one team NHL:
0.82 PPG
- Ray Bourque, aged 19, twenty-one team NHL:
0.81 PPG
- Ray Bourque, aged 40, thirty team NHL:
0.74 PPG
- Joe Sakic, aged 20, twenty-one team NHL:
1.28 PPG
- Joe Sakic, aged 37, thirty-team NHL:
1.22 PPG
- Jaromir Jagr, aged 19, twenty-one team NHL:
0.99 PPG (not in top 30)
- Jaromir Jagr, aged 43, thirty team NHL:
0.84 PPG (top 20)
Point being, at least 80-100% of the world's best players have always been in the NHL, same in the 1930s as today. History proves, beyond a shadow of a doubt, that elite players usually transfer their skills across eras.