I think you are right. There are many people in their 40s who grew up with online games, my father included :). Although I am still fairly certain that online games weren’t as prevalent back then as they are today, thus many parents don’t quite grasp the concept.
EDIT: I would like to add that even people who didn’t play online games, such as my mother, still played on the atari, for example, and know the concept of “unpauseable” games. So I think that it mostly comes down to demographic. In my group of school friends (a few years ago) some parents were in the know and others weren’t.