I think there are a whole lot of contributing factors to the situation in schools and with children and teenagers in general (and obviously these factors will vary somewhat from country to country). I liked Adolescence for not giving a single answer, and for not spelling out things plainly to viewers, but rather letting the story speak for itself, and viewers draw their own conclusions. (Unfortunately there's been a rather stupid knee-jerk reaction here in the UK, where it's captured the cultural moment so thoroughly that even our Prime Minister has watched it and mentioned it in interviews, and people are rushing to say that there is clearly one simple solution to all this: to take smartphones away from kids, to ban them from social media, and so on.)

You don't really need to make a fifth episode to the show, because it's really clear from the second, third and fourth episodes that nothing has changed beyond the circumstances of this one boy, his family, the death of his victim, and its effect on her loved ones — the same factors that led to all these events still remain.