There were some stars from that era though-Taffy Abel, Frank Brimsek, Mike Karakas. Yet by the mid 1950s there wasn't a single American trained player in the entire league.
In a sense, it reminds me of what was often said about black quarterbacks. "If you were a black quarterback, you had to be dominant because otherwise they'd switch you to another position." For the Americans in the early days of the NHL, the same thing applied...you
had to be dominant because otherwise the teams would just grab a Canadian to fill the spot.
We can throw Sam LoPresti in the mix as well; he filled in admirably for Karakas for two seasons before being drafted into the Navy during WWII. Cecil Dillon was another; he's also the first Ohio-born NHLer.
I think the spike and then decline is based on the following:
- More Americans entered during the NHL expansion period of the 1920s
- Those who could play stuck around through the contraction
- Most were old by the time WWII hit
- The league's contraction to six teams reduced the number of spots available
- There was an anti-American bias to some extent
- The NHL wasn't paying well enough to justify leaving good jobs during the post-WWII time period
The Minnesota natives (Brimsek, Karakas, Romnes) swore that there were plenty of local players just as good or better than they were, but they refused to take a pay cut to play hockey and have to give up farming, mining, or whatever else they did.
If we adjust the qualifications to simply "players who played in more than 25% of the season", we would already see a drop in number of players over the span of the 1930s.
1930-31 - 10 played at least 11 games, 1 played fewer (plus one goalie with 1 game)
1931-32 - 9 played at least 12 games, 1 played fewer.
1932-33 - 10 played at least 12 games, 0 played fewer.
1933-34 - 9 played at least 12 games, 2 played fewer (plus one goalie with 6 games)
1934-35 - 10 played at least 12 games, 1 played fewer.
1935-36 - 9 played at least 12 games, 1 played fewer (plus one goalie with a full season)
1936-37 - 7 played at least 12 games, 9 played fewer (plus one goalie with a full season)
1937-38 - 9 played at least 12 games, 5 played fewer (plus one goalie with a full season)
1938-39 - 7 played at least 12 games, 1 played fewer (plus two goalies with a full season)
1939-40 - 4 played at least 12 games, 4 played fewer (plus two goalies with a full season)
1940-41 - 3 played at least 12 games, 2 played fewer (plus two goalies with a full season)
1941-42 - 2 played at least 12 games, 4 played fewer (plus two goalies with a full season)