Maris and Aaron: still home run kings.

[Polk]

There was an unannounced change after the Players strike. Prior to that you could count on one hand, er two hands, the number of players who had hit 50 or more HR in a year. This was a favorite past time of my friends after George Foster became the latest member.

After the player strike, MLB decided to make the game more "Entertaining" by making it easier for the batter and since then there has an explosion in the number of players @ 50+ HR's.

You can look it up

Fun conspiracy theory, but doesn't really hold up under analysis. The average number of home runs hit by the league leader in the AL in the five seasons before the strike was 43.2. In the five years after the strike, that increased to 52.4. Over the last five years though, the number has declined again to 46.4 (including under 40 the last two seasons). Similar trend in the NL. 41.2 in the five seasons before, 54.2 in the five after (a number heavily skewed by McGuire's two 65+ campaigns), 50.8 over the last five. The differences can easily be explained by natural variation and the widespread use of steroids in the late 90s.