It's because roughly 90% of all people between the ages of 12 and 60 have a camera with them at virtually all times. The camera is integrated in a device with which they are interacting most of their waking hours. They use that camera to make still photos of their lunch, their dinner, their dessert, their dog taking a pee, etc. Thus, a typical consumer today shoots more footage than a full-time t.v. news cameraman might have, back in the day. If any of that footage strikes them as being the least bit "newsworthy," they will post it (at virtually no cost to themselves) on line, where it will get more eyeballs viewing it than a news cameraman working for a big-city t.v. channel back in the '70s might have gotten.
Question answered?
Regards,
Actually, that partially answers my question (and I knew that about millennials) but he was driving. Why would you be filming while you’re driving? That makes no sense. Do you see someone pull up next to you and automatically start the video function on your phone?