It’s an outdated attitude. When I was in highschool I knew of a handful of classmates who were apartment hunting for their 18th birthday. Some parents thought it was best to get the kid out of the craddle as fast as possible so they could start facing the real world. Others, their parents hated being parents and wanted the kid out. Keep in mind that back then a highschool student with a decent part time job that gave over a dozen or so hours a week could just barely afford a starter apartment, but it was doable. Now that same job wouldn’t be enough to cover the electricity bill. Today it’s an incredibly heartless thing to do to a teenager.