What was the real reason for the flood, and why is it seldom if ever talked about?

he Bible makes very clear the reason for the flood; The Lord saw how great man’s wickedness had become, and that every inclination of the thoughts of his heart was only evil all the time. The Lord was grieved that he had made man on the earth, and his heart was filled with pain. So the Lord said, “I will wipe mankind, whom I have created, from the face of the earth—men and animals, and creatures that move along the ground, and birds of the air—for I am grieved that I have made them”—Genesis 6:5-7. It really is a real-world example of what the prophet Habakkuk was talking about when he said, Your eyes are too pure to look on evil; you cannot tolerate wrong—Habakkuk 1:13a. And certainly David understood that sense of God’s immense displeasure with sin; he wrote, You are not a God who takes pleasure in evil; with you the wicked cannot dwell—David, Psalm 5:4. The flood presents some indelible truths about God as we look forward to the future:
(1) God will judge the world (He’s obviously done it before—sin has consequences). As the apostle Peter wrote, For if God did not spare angels when they sinned, but sent them to hell, putting them into gloomy dungeons to be held for judgment; if he did not spare the ancient world when he brought the flood on its ungodly people, but protected Noah, a preacher of righteousness, and seven others; if he condemned the cities of Sodom and Gomorrah by burning them to ashes, and made them an example of what is going to happen to the ungodly; and if he rescued Lot, a righteous man, who was distressed by the filthy lives of lawless men (for that righteous man, living among them day after day, was tormented in his righteous soul by the lawless deeds he saw and heard)—if this is so, then the Lord knows how to rescue godly men from trials and to hold the unrighteous for the day of judgment, while continuing their punishment—II Peter 2:4-9.
(2) God continually hates sin. He hates it because it is rebellion against Himself, His ways and His word.
(3) Despite our sin, God shows mercy. He provided an opportunity for salvation with Noah and the ark. He has provided an opportunity for salvation with Christ and the cross. One reason that judgment will be so certain and so harsh? To refuse His salvation is to refuse His very best—His Son.
(4) Nothing will escape God’s scrutiny. As the author of Hebrews says, Nothing in all creation is hidden from God’s sight. Everything is uncovered and laid bare before the eyes of him to whom we must give account—Hebrews 4:13.
(5) Studying the flood will give us insight into the conditions that will exist when Christ comes again: Just as it was in the days of Noah, so also will it be in the days of the Son of Man. People were eating, drinking, marrying and being given in marriage up to the day Noah entered the ark. Then the flood came and destroyed them all. It was the same in the days of Lot. People were eating and drinking, buying and selling, planting and building. But the day Lot left Sodom, fire and sulfur rained down from heaven and destroyed them all. It will be just like this on the day the Son of Man is revealed—Jesus Christ, Luke 17:26-30. Life was normal and ordinary when, in an instant, everything changed. No one was looking for any consequences to their lifestyles. No one was living beyond the moment.
(6) Noah showed great faith; the author of Hebrews takes note of this: By faith Noah, when warned about things not yet seen, in holy fear built an ark to save his family. By his faith he condemned the world and became heir of the righteousness that comes by faith—Hebrews 11:7. It’s not that Noah simply had faith; it’s what he placed his faith in. And he believed in what God was doing and saying without having to see the end. He trusted the future because He trusted the one who held the future. We can too.
As far as why it’s not talked about more, that would be a matter for pastors or teachers to ponder. It probably should be talked about more because it certainly can be viewed as a blueprint for the future. There is a profound judgment yet to come, with an even more profound salvation still being offered to provide a way of escape, for anyone and everyone who believes. If that’s not relevant to believers and nonbelievers today, I don’t know what is.