How does cultural change happen?

I would say it's often because people see individual examples in action. Some people follow those examples. Then more do. You are more influential than you think.

> A few decades ago we explained that personal responsibility isn’t the solution.

I've never seen that argued persuasively. All the arguments I've seen are the usual hopelessness for democracy, lack of agency, and victimhood.

Lots of people acting in the same way is the foundation of democracy.