My thought was that if Christian creation just got of foot-note in creationist science because a much better, polytheistic creation theory existed, the Christians might back off on the idea of having their kids taught about a pantheon of bizarre Mayan gods, human sacrifice, self-mutilation, and the importance of carving out the beating hearts of captives.
You erroneously assume that creationists actually CARE whether or not what their education system accurately reflects reality. That is entirely besides the point.
Creationists want the education system to conform to CHRISTIAN DOGMA, not to science, not to logic, not to reality, and not even -- strictly speaking -- to the Bible. They want their chosen worldview to be taught as unquestioned truth because doing so allows them (they think) to maintain a lockstep moral and political power bloc that conforms to the priorities of their social and political leaders.
IOW, they push creationism not because they've examined it and believe it is true, but because they have been TOLD it is true by the people they follow and because questioning the moral authority of their lives makes them deeply uncomfortable.
Well, that would be kind of the point of it. To them, teaching that there are many other gods is far, far worse than evolution. It goes back to the core fight between Christianity and pagans, without the panoply of pagan gods being taught as silly myths, and worse, it's not a cute, harmless polytheism from India, it's a screaming, human sacrifice paganism where they peel people's skins off and wear them as coats. It even freaked the Spanish conquistadors out. Al Qaeda and ISIS would run away screaming. Nazi SS officers would wet their pants. Baptists would burn the schools down before they would let anyone seriously teach Mayan cosmology and religion.
And yet scientifically, the Mayans were probably closer than anyone else, because the truth is not what most human cultures assumed. Whereas Christian theologians spent countless man-years agonizing over why God created diseases, and trying to explain it away, the Mayans thought that some gods think it's funny to watch humans twitch and die, bleeding from both ends, because they didn't take the trash out (blame Trashmaster).
Their religion also makes testable predictions about the world, which can be experimentally verified or refuted. That puts it into the domain of science, which is something you can't do very well with Christian creationism, which just makes excuses for everything.
As one archaeologist once put it, all the alien races on Star Trek are recognizable elements of recent Western civilization, but the Mayans were truly alien. They were so alien that the captive who knew he was going to have his skin peeled off and worn as a coat would party for a week with the family that was going to do it, because to get your skin peeled off and your chest ripped open and your heart ripped out was a great honor that had cosmological significance. Mayans would fight battles to
lose their armies, hoping their warriors would be defeated, brutally tortured, and butchered in a vivid public display. And it actually makes sense, given their creation stories.