I think this a bit of a generalization. I teach basic English to students here in Thailand, many of which are teenagers. I think the main problem is that most teenagers don't know about the joy that can be found by reading books, mostly because they've been forced to read rather boring prescribed books at school. Once you show them that there are books written that align with their interests, that all changes. I've had kids get so excited about reading a book, that they finished reading it by themselves and asked me if I could find them some more. So with a bit of help and proper curating, teenagers today can still enjoy reading. I'd say it's up to the parents (as they know their kids well) to help their kids find interesting books for them to read. Once that seed is planted, it will certainly grow.