Does it has anything to do with smartphones though?

It looks like it is simply a case of caring for your kids. Smartphones are an easy solution for parents, give them one and it keep your kid occupied while you are doing your stuff. Having your kids "socially connected" typically involve getting them into clubs and the like. For hiking, they probably need someone to get them to the hiking place and at a younger age, accompany them. Even more complicated now that leaving your kids live their live outside without constant physical supervision is more and more frowned upon.