The question is imo, what made big 3 so good? Why does the next gen( so did lost gen) struggle so much against them
They are good. But not THAT good to deny Slam wins to next ATG till they become 35-36. Nadal and Djokovic were beating Federer during his peak/prime years. If there had come a new ATG in say 2014 - I have no doubt he would find the way to win Slams beating Big 3 even back then. He would definitely dominate 35 yo dinosaurs and send them to retirement for sure. Two generations were terrible that helped Big 3 to inflate their numbers..