Beliefs that a person holds deeply, holds on faith without requiring proof, bases their life choices on, and evangelizes as the truth.
By that measure, aetheist San Francisco is the most religious place I’ve ever lived. The religions focus on the right way living or eating, and the evangelism is off the charts.
I would argue that the younger generation isn’t significantly less religious, but rather that they’re all inventing new religions or following scattered and informal tribes online. It’s like a new philosophical primordial soup from which I suspect we will see organized and “formal” religions emerge given sufficient time.