To Campbell a convincing mythology is one that is in sync with the cosmology of the the time.“
An essential point, indeed! (Campbell might be more likely to use the phrase ” a living mythology,” but he would agree with your thought).
To the scientific sources of a fundamental change in our perception of the world (the discoveries of relativity, quantum mechanics, the expanding universe, and the space program), I would add the Information Age – specifically, the invention of the internet and cyberspace. These have impacted us in ways both good and bad: on the one hand, making the world a smaller place in many ways, creating a universal monoculture often at odds with local culture; and on the other, upending norms and fostering a divided society.
In my daily life I am often caught up in the fray – the “fighting over sandwiches” that Campbell notes marks the priority of most humans – but I’m also aware, on a deeper level, that it’s all an amazing Dance.