What's the point of comparing players from different eras if you don't control for the environment? Obviously soccer players today are better trained and condit

What's the point of comparing players from different eras if you don't control for the environment? Obviously soccer players today are better trained and conditioned than they were 50 years ago. Same for football players, and baseball players, etc. If that's the standard, then the GOAT will almost always be whoever the best modern player is, which isn't a very interesting discussion.