Actually there is a very good chance it could be put into school textbooks; the reason being the way text books are sold in this country. Most grade school and high school text books are printed and marketed at the national level. Trying to see that all students have the same information at their disposal no matter where they live. All well and good, IF states had equal input as to what should be in textbooks.
But, as always, the bottom line is money. And the bigger states buy the most books. The state that buys the most textbooks is Texas. So Texas gets a disproportionately high level of input as to what goes into these books. If they disapprove of the material, they might not buy the book for their school systems. No book publisher is going to take the chance of ticking off the Texas state school board. And, of course, Creationism support is HUGE in Texas. Add to that a rabid conservative director of the school board and the issue made national headlines two years ago.
He demanded Creationism be put in the science section of textbooks. There was a huge fight, of course, and in the end the inclusion was cancelled. But it came VERY close for a few months there. With most of the country under the control of religious conservative republican governors right now, the separation of church and state is as this as it has ever been, probably in the history of the country. Scary times for those of us who believe our government should remain completely secular the way the Founding Fathers intended.