And Babe Ruth and Sammy Sosa weren’t hitting against the same kind of pitchers. I’d say Ruth and Gibson were probably facing pitchers and fielders with more in common than those of different eras. Stats always come with context. Doesn’t mean they don’t belong together in the same list.
That used to be really common. Movie novelizations would come out before the movie, along with soundtracks, etc. It was part of the promotional campaign.