It's not really that surprising when you know the whole blue and green bubble thing was targeted at teens and young adults, the two groups feeling the most societal pressure to fit in. Turns out when you make people not owning your devices clear outsiders then people not wanting to be outsiders will buy your products.
The fact that Android is less popular among younger generations poses a challenge for its future success in the US market.
I think this concern is overstated. While nobody knows the future to certainty and there's value in brand familiarity, there's also a huge difference between getting your phone on your parents' plan versus managing the plan for yourself or your family.
Priorities change, and I'm not just talking about cost here. For one, I think people care less about what others think as they get older, and that peer effect is a major selling point on Apple products.
I'm the 10th teen using an Android. Degoogled at that. I think one of my friends is looking to switch from iphone to android so I'm converting some people here.