The gods took a heafty blow when the Lunar Rains occurred. How can you believe your gods love and protect you when there are rocks and monsters falling out of the sky?
The Traditional DnD gods once ruled this land, and still do, ostentatiously, however their power has been reduced greatly. Cleric magic is now finicky.
The lack of initial protection and subsiquent bootstrap recovery has lead to two things: there are an awful lot more athiests in the world than at any point in its history; and a new religion has immerged following an entirely different sort of god.
Dortak, The Great Engine
The spread of technology and science inevitably brought around the belief in a new sort of god. Instead of bickering and warring between themselves, proponents argue, a true god would be one who simply built the machines of creation and set them into motion. No one knows who came up with the name, but it stuck. Dortak’s nature is both engineer and engine. He both designed the machines that run creation, and is that machine. He has no clergy. Yet. But rumors spread that he has a few prophets and saints running around, those chosen to fulfil his will.
The truth is that the religious cosmology of the plains is mostly unchanged. The Lunar Gods have challenged the Planar Pantheon, and their opening gambit did sorely cost the Gods of Highpoint, but despite the shifting opinions on the surface, they still exist and have always.
Dortak on the other hand, does not and has not. But he might yet. And I’m not sure whether that’s a good or bad thing.