I think there's too much money in the game for the younger players to be hungry..
I was reading the sampras book and he talked about becoming a millionaire after he won the US Open.. cut to now you have players like tomic and kyrgios who are millionaires with their results, it shows it's a different tour these days...
back then it seems it was more dog eat dog.. Now it's more like a buffet with plenty to go around for everyone..