What's changed is that we no longer believe in the future, that the future could be better than the present.
Further, modern media takes that even further. Plenty of producers, marketing people, people with the purse strings just want more of whatever was popular last year. Which creates a trend to produce more of the same.
Yes, real life events are also an influence but similarly, one extremely popular title can influence followers for years/decades.
To put it another way, if there was no Walt Disney would there be 150+ famous family oriented feel good animated movies that have influenced so much of our culture OR, would we have some entirely different culture because one artist (or team of artists) works didn't have that particular level of influence.
https://www.newyorker.com/magazine/2003/12/22/the-ring-and-t...
In the context of this essay, our moral future is far less certain. The cold war had an old narrative to it, with easy villains. The world of today makes it more difficult to avoid the nuance. It can even explain why so many AAA game titles fall back to derivative, Tolkien-esque settings.
This has the ring of truth to me.