My study of history in WHEE has a lot of insights into the history of religion, and the issue of the Axial period and modernity is one of the most confusing. The issue requires a careful study of the whole model, however.
I am not promoting Xtianity here, but it remains true that the only religious entity given the macro transformation effect (so visible in the Axial Age) in the modern transition is Xtianity in the Reformation. That is the result of the sudden restriction of parallel emergence to a single track in modern times.
The Protestant Reformation creates a form of Xtianity that starts to dissolve, as it were, and in the seventeenth century we see the system moving into a new set of positions. That’s the reason for the confusion over the secular in modern times. A close look shows that buddhism rapidly becomes an object of study and diffusion, as if this macro system were trying to correct its flaws.
So the question of these religions in the future is going to problematical. Students of the New Age spectrum could care less about the Reformation, and I am not promoting that. But the issue can help New Agers understand how their movements tend to stall and not go anywhere.
A good example here is to see that New Age movements are lucky to have fifty thousand members, while in the past generation or so Xtianity has acquired ten million converts. This situation requires careful thought.