Despite the truisms that each generation tends to think things are going to hell, this time they really are going to hell.
A life unmediated by machines is qualitatively different from one that is. Books, TV, video games were self limiting compared to the modern internet—especially social media—delivered via smartphones. Why?
1. Because they change the way we acquire knowledge. Anyone who has taken trips to foreign countries before smartphones and GPS would have been forced to talk to _people_. We had paper maps and guidebooks (Lonely Planet, my ass it's today's planet that seems lonely), but when those didn't match the reality on the ground, we were forced to ask people. Now we can all go along in our own little bubbles with our phones and experience things without talking to people.
2. It is reducing our connection to our bodies and bringing us up into our heads even more. To live a full life means to be in contact with the physical world, and to act within it.
3. As has been said above, the incentives of the makers of smartphone apps are almost always at odds with living a meaningful life. The apps almost always will try to increase your engagement with your phone, and because time isn't infinite, this means decreasing your engagement with life.
4. Because of the portability, smartphones are omnipresent. Some people even check them while they sleep.
And the sad thing is that, yes, it takes people who have lived almost their entire lives outside of the 'app' ecosystem to tell younger people this.
The apps and the phone and the habit of using them all the time have changed you developmentally. You can't see the water your swimming in, but there are some of us who still can.