Haven’t read the Times article yet, but sometimes true anxiety does not manifest until a kid is out of the house. Was just talking to one of my kids the other day. He had a stressful situation and said that it went fine objectively but the anxiety made him feel it did not. I was trying (and failing) to explain that everyone feels anxious in those sorts of situation and he explained that prior to developing anxiety he knew what being “normal” anxious is and that this is very different. He had many moments of being outside his comfort zone and also support for those things that made him anxious (which were pretty limited as a child, storms being one). Not sure that parenting (assuming in the range of decent parents) really impacts this as much as brain chemistry.
I also think that the label and the availability of seemingly benign meds has played a part in the increase. I recall not being able to eat or sleep and feeling faint before anxiety-inducing events, but have learned to talk myself around. Not sure if I was a student today that I might not have labeled myself with anxiety.