Today, I was asked the question, "Who is in Gun Culture 2.0?" My knee-jerk reaction was this:
Members of Gun Culture 2.0 know and follow
Colonel Cooper's Four Rules.
I count derivatives and evolutions of his rules (such as the NRA's Three Rules), too.
There are other ways to differentiate between Gun Culture 1.0 and 2.0, but I think Cooper stands as the dividing line, in many more ways than just safety rules.
One of the other, somewhat counter-intuitive aspects of Gun Culture 2.0 is that the 1.x line is alive and well. 2.0 was released the 1950s, and it's taken quite a while to get the word out. It's not always easy, but 1.x is always upgradable to 2.0.