Millenials choosing to live at home?

I just read another story about millenials choosing to live at “home” (with their parents). I have to say, I don’t understand that at all. I was ready to leave the house and be on my own when I was 17, but I knew I couldn’t make enough money to do that, so I hung around until a little after I graduated high school. Why young people would willingly choose to live at home with their parents rather than be out and on their own is an attitude I can’t grok at all.