Most new gens DO NOT think they are better... that is some illusion that Old gen people have made....
Generation does not effect skill as once u have like 2k hours u basically peak anyway... only thing making u better or worse after that is the meta e.g. spammy, s keying, chambering.... or who you are in a team with.
for example... someone who was good in 2k14 when people were more aggressive will probably get dunked on by like extazzz when people are most patient and cancer.
Even if i'm wrong there, the generation thing is ridiculous, most new gens are humble or if they think they are better its not because they think all new gens are better its because they just have an ego and genuinely believe they are better.