Student or Learner
"Woud/could/might" have pp" can be interpreted as pure presumption(with no facts provided) or counterfactual past(facts provided). In this paragraph, this seems to be a counterfactual past considering modern things like "cellphone ringtones and playing video games" that adults of earlier generations didn't enjoy, but considering "visiting amusements parks", it could be pure presumption.
What do you think? It is ambiguous, so I feel I'd better not so strict in judging it.
gu14)A popular saying claims that once we grow up we must set aside childish things. Yet modern adults enjoy downloading cellphone ringtones, playing video games, and visiting amusements parks just as much as kids do. Today's grown-ups are showing a commitment to keeping in touch with their playful side. Whether it's purchasing youth-oriented products or getting together to enjoy a board game, this new type of adult is refusing to set aside childish things. Despite the many responsibilities they face in their lives, these grown-ups are allowing themselves to enjoy things that adults of earlier generations would have considered appropriate only for children.
(not a teacher)
I would consider it to be a "presumptive" statement.