The problem with these articles is that everyone who works with Millennials suspects something along these lines is true... but there's so little DATA.

True, there's not much data yet. 

My takeaway from the article is that resilience is a consequence of learning to do things independently.

In previous posts (for example, here and here), I have described the dramatic decline, over the past few decades, in children’s opportunities to play, explore, and pursue their own interests away from adults. Among the consequences, I have argued, are well-documented increases in anxiety and depression and decreases in the sense of control of their own lives. We have raised a generation of young people who have not been given the opportunity to learn how to solve their own problems. They have not been given the opportunity to get into trouble and find their own way out, to experience failure and realize they can survive it, to be called bad names by others and learn how to respond without adult intervention. So now, here’s what we have. Young people,18 years and older, going to college still unable or unwilling to take responsibility for themselves, still feeling that if a problem arises they need an adult to solve it.

Yeah, both sad and alarming. As a kid I walked to school alone on my very first day of primary (my Mom, unknown by me, did follow from a distance, but only that first time). I always walked to school without adult supervision regardless of the weather, either alone or with school friends. We had to deal with bullies fairly regularly, and we regarded it as an unfortunate and normal thing. 

Most of my play time, once I started school, was outside without adult supervision. I got into things that I suspect would freak most parents now out, and prompt them to not let their child out on his own. I did have some accidents that did scare my parents. For example, I fell through the ice of a pond one winter when I was 8 years old, and almost got hypothermia. I got home by myself. But despite the accidents, they rarely supervised any of my play activities. In fact, my friends and I preferred to be unsupervised.

I guess the hard part is to find a way that gives room for a child to develop resilience without putting them into danger.