I'm not over thinking it at all. You have to set rules to make these comparisons make sense.
Flagg has it right. If you're taking 1987 Gretzky and putting him on the ice in his 1987 gear with his 1987 training and 1987 coaching, I bet he gets owned.
But if you take Gretzky, have him born in 1985, drafted in 2003, and in the NHL that coming season, yeah he's going to be amazing.
Have Gretzky born in 2000, drafted in 2018, he's going to be the best player in the world.