Current Pet Peeve: Young characters with names that haven’t been popular for decades (Peter, Susan, Barbara, etc).

I'm reading a book that I won't name, because this actually applies to quite a few books. Why do so many authors use names that haven't been popular for decades? In the book I'm currently reading, the majority of the main cast are teenagers. It is set in modern times, like 2020-ish. And yet, they [...]