If we can't even determine if stories in the Bible are historically accurate or not, then why should I even bother reading it? Genesis has a clear timeline of creation and other books of the Bible clearly make references to Adam's existence and his familial line repeatedly. How can this be taken anything but literally? I don't understand.
Because the Bible isn't a monolithic tome, it's not a book. It's a library of books. The Bible needs to be approached as a library, not as a book. Do you immediately assume that if your local library carries a work of fantasy fiction such as The Hobbit it therefore cannot have any historically accurate material, say a biography about Thomas Edison?
If you think it's a little silly to assume that your local library must either have all literal texts or all non-literal texts, then you can see why it might seem a little silly to some of us for people to approach the Bible (a library of books) that way.
Genesis is first and foremost a book of the Torah. The Torah being the five books also known as the Pentateuch. As Torah the chief purpose of the text of Genesis is, like Exodus or Leviticus,
instruction. And one will find precisely that within the stories it presents. Consider the stories about the angelic visitors to Abraham, and Abraham welcomes them and presents them with a feast; this story is followed immediately by angelic visitors going to Sodom, where they receive the stark opposite of hospitality, they encounter a violent, rapacious mob. Think it's a coincidence that these two stories exist right next to each other, no that was done intentionally. The Israelite who reads of Abraham's hospitality would understand that this is what God required of him (or her), and Sodom's cruelty stood as a stark contrast to Abraham's hospitality. And that's exactly how ancient people read this text.
So the chief purpose of Genesis isn't history. The chief purpose of Genesis is instruction. It contains mythology and stories (some of those stories may or may not be entirely historical--but that is fundamentally unimportant) framed as they are to provide lessons, teachings. So, for example, in Genesis 1 the teaching is that God--not the natural powers--are to be revered as Divine; indeed, the celestial powers--the sun, moon, and stars--are downplayed, they are not divine, and they are created not on the first, but the fourth day.
Secondly, Genesis, as the name itself (and in Hebrew Bereshit means the same) is the book of
beginnings. It is Israel's prologue, the religious and cultural prologue that leads toward the culminating moment in Israelite history--the giving of the Torah on Sinai to the nation by which the people were made God's covenant people, the covenant nation. By which Israel had its religious, cultural, and national identity. Genesis narrows the scope of the story down from everything "the heavens and the earth" down through generations to Abraham, then Isaac, and finally to Jacob and his sons.
My own reading of Genesis doesn't have Genesis start becoming "historical" (in the way we moderns understand history) until we get to Abraham. The pre-Abrahamic narratives are mythology. Myths. Not falsehoods (that's a poor understanding of what a "myth" is); but rather they are profound teaching-stories filled with important archetypes.
That Noah and his boat is a myth, and something that did not happen in real history, doesn't make the story unimportant. Neither does that mean nothing else in Genesis (let alone the whole of the Bible) non-historical.
Because this is what the majority of Christians believe and what is taught in Christian schools?
What is the "majority" seems to be an entirely subjective opinion. There are around 2 billion Christians on this planet, so when someone says a "majority of Christians" then that has to mean approximating upward to that 2 billion point. At the very least "majority" would require 51% of all Christians, and thus approximately over a billion.
You may be correct that a "majority" holds to a view that approximates something as you present it--but I sincerely doubt you have the actual statistics to back that up.
Most Christians aren't American Fundamentalists.
Most Christians belong to either the Roman Catholic or Eastern Orthodox churches. The majority of Protestants aren't Fundamentalists either, but belong to various mainline Protestant denominations--Lutheran, Presbyterian, Anglican/Episcopalian, etc.
So if your entire premise is to say the word "Christian" and mean only "American Fundamentalist" then it's a bit like saying the word "green" and meaning only
Dictyota friabilis (a kind of green algae). Sure it's green, but it's not the only green thing around, and it isn't the most representative of all green things.
-CryptoLutheran