Heck, I've come across some couples near millennial age who share the same e-mail account. It boggles my mind.

Apple could add multiple user and family functionality to iOS and iCloud. Most smart phones these days have work related e-mail, documents, and images which should have restricted access. Such data is usually wide open when parents hand their phones to their kids who may leave it unlocked, playing videos.

I setup users on my android travel phone which I lend to immediate family so I don't get stuck with their browser history or e-mail. Or they can be reminded to clean the device caches and logins before returning. Friends have setup limited users for their kids. Amazon has a family/household concept for Kindle.