I think you are missing a critical point -- most people seriously don't care about the age of the Earth, at all. So if you ask someone "did God create the Earth in its present form", you are not identifying whether or not someone is a young Earth creationist, but simply giving the prompt "do you believe in God enough to say 'yes' on a random survey?"

One survey found that 25% of Americans don't know that the Earth orbits the sun. This seems like a non-religious question to me, and thus I am willing to take it as a general indicator of 'how much Americans care about basic science'. So I would split that 42% into two groups: 'Americans who strongly believe that God created the Universe in its present form' = 17% (ish), 'Americans who guessed wrong and/or would like to weakly signal that they are Christians' = 25% (ish).

Most people just don't care enough to alieve about science. However, I suspect that more people do care enough to alieve about politics, and are willing to base their political ingroup on religion.

Whether someone is an alieving Christian can be hard to determine because of where you set your threshhold--typically people act as though some things about Christianity are true but not others. But entirelyuseless brought it up in the context of the people who run the government and I think it's exceptionally clear that most of them aren't. I certainly doubt that the members of the Supreme Court who voted for gay marriage are either evangelicals or religious Christians.