Did you ever consider that the slant might be from the original builder planning for the house to settle over time? Some old places were built with a slight lean so they would even out after years of ground movement. It's not just a nautical thing, it's actually pretty smart. That means the person who made your house thought ahead about how the land changes. A lot of modern construction doesn't account for that kind of natural shift. So your floor might be telling a story about good old-fashioned building sense.
So the builder planned for my house to settle into a crooked mess? That's not smart, that's just guessing wrong. If they wanted to plan ahead, they could've used better dirt under the foundation. My floor's story is about someone cutting corners, not some genius old-timey wisdom.