I think it's very clear in the texts of the major religions that the set of rules they put forwards is, indeed, meant to be followed for eternity. The Bible doesn't quote God as saying "don't do these certain things unless, thousands of years from now, you have a better moral and scientific understanding than the Iron Age Jews writing this and realize that it's immoral nonsense." Christianity isn't supposed to do that, and it doesn't. It's a nice thought, but one that doesn't stand up to criticism.