Shabbat shalom, Josh Hunt.
I don't, nor would I. I think that it still exists in its own circle of teachings and books, but to me, Postmillennialism is just too close to Amillennialism. Both suggest that we are already in as much of a "Millennium" as we can expect.
Postmillennialism was big before the world wars began, but with WWI, it began to lose its credibility. WWII all but destroyed its following. The concept that "the world will get better and better until it's good enough for the Messiah to return" is too much like the theory of Evolution to me. The whole idea that we can "pull ourselves up by our bootstraps," to me, sounds like a slap in the Messiah's face! As if to say, "Thanks for the leg up; I've got it from here."
No, I'd not make that turn in my thinking. I believe it's much more sound to take the "top-down" approach, rather than a "bottom-up" approach. It makes much better sense that people, left to themselves, are going to wind down in their morals, not wind up, like science teaches the Second Law of Thermodynamics, entropy, a winding down of energy's complexity - becoming more and more useless heat, not the theory of Evolution, a winding up of complexity as more and more cells and organisms become ever more complex. We NEED the Messiah to return and give us HIS perfection! No one can attain perfection on his or her own, not even collectively as a "church!"
It's like the difference in Geometry between deductive reasoning and inductive reasoning. Deductive reasoning is more absolute. One reasons from the general to the specifics. It's much more difficult to reason from the specifics to the general through an inductive method because NO ONE can know every possible particular! To reason through inductive reasoning, one must take a "back-door" kind of approach: Suggest the OPPOSITE of what you are trying to prove is true, and then reason to a contradiction, forcing the opposite to be true.
Anyway, that's my take on it.