I think we still heavily depend on mythology and folklore for our stories today. But I think we are finally past the point where those can become more than just stories told for entertainment or teaching purposes. But I'm not sure about that, given that Mormonism and Scientology are quite recent and have become established religions with small but devoted followings.
It might be more difficult today to create a new religion, even one built on the framework of previous ones. But I might be overestimating just how powerful such ideas can be, and just how badly people want them to be real.