Two things that stand out instantly:
- the calibration of the devices they used to measure objects at high speeds, like flying pucks, has to be off. There couldn't be that many people shooting that fast.
- Look at the speeds of the league's fastest players (I assume those are the fastest) and then look at the team averages. This is a massive gap between the league's fastest, average, and worst skaters. You have Hull at 29, a handful of players within 2 mph, but then the fastest team only averages 22. Which means for every player at 25, they likely have one at 19. Look at the NY Rangers, averaging 19. So for every guy at 22, they'd have to have a guy at 16 to average 19.
There were some really slow players back then, compared to the stars. There were players who literally could barely skate half as fast as Bobby Hull.