Yes, after a few hundred years of turmoil, a great leader will arise to set things right. Afterwards, things will procede as they usually do until we reach a point much like today in terms of religion and morality, though not of science and technology.
Then after centuries of darkness, a great leader will come forth and establish order. Afterwards the world will evolve as expected to a condition not unlike the present in terms of irreligion and immorality, if not science and technology.
But fear not, a great leader shall arise who ...
So it goes. Great leaders and renaissances don't last. Perhaps it's better to make do with what we have, rather than to wish for great changes. There's something more than a little chilling about the "great leaders" previous generations expected to save them.
And what -- on earth or in heaven -- makes you so sure that those leaders who arise will be Christian or any more Christian than today's leaders? Or are you just choosing the one or so who might be Christian and ignoring all the other world saviors who'll present themselves?