And herein lies the problem with your assessment. If the Bible is only "valid" from "the perspective of the authors of the book, at the time", then doesn't that fly in the face of an ever-present, unchanging, everlasting God? Would not this all-knowing God see that we in the modern world would come into being, and design the Bible so that it would be just as valid, and accurate for us, today, as it was for the writers of Genesis? Or was God not capable of such forethought?
I did not say it was only valid from the perspective of the authors of the time. I said people, today, miss the perspective of the authors of that time period. The authors wrote a vivid, picturesque view of the goodness of God that humans were failing miserably at emulating. The story was about human corruption which was washed away...at least for a time.
The same would be very true today. For example, don't some view the liberal agenda and the Democratic Party (or the conservative agenda and the Republican Party) as corrupt/inept beyond belief? If a someone in our time about this and told of the day where the __________ Party crumbled into non-existence because of how corrupt it had become, pointing out divine justice finally had its day, might not later people, unfamiliar with these times, decry a divine justice that would destroyed an entire party, thereby missing the original point of such a story?
The Bible is a timeless revelation about God. First it tells of God's goodness, comparing that goodness to humans failing at goodness. The next revelation about God is His justice. Notice people striving to become as just as God by keeping His law always before them. The third revelation about God is His love, the love of a father who would devote and ultimately give his very life to his children.
Corruption cannot stand in the face of Goodness, Justice, and Love. These are the timeless tales of the Bible, so simple, yet still flying over the heads of some people today. In their confusion the corruption becomes their hero and anyone ending corruption is seen as the ultimate evil.