I understand it as well as any old fossil can. My kids have such a variety of social media apps that give them a constant stream of content. It comes in so hard and heavy that wasting a half hour on one single piece of content is almost unthinkable.
You notice the phone because they are always carrying it, but at least my kids will head over to a tablet or laptop for better viewing when at home. In addition, one can subscribe to certain content and then have it pushed at you, which conventional TV doesn't do. Basically, why wait for content to be available, when there is content out there that is both more timely and readily available when you are?