Genesis 8 significant point: it took 40 days and nights of rain to destroy every living thing. That means it took a long time for everyone to die. Noah was righteous when the world was worth destroying and he got tasked to build the ark. The lesson here is that at some point YHVH is going to be done with this world again. He will make that decision, and it will be over. Even though the destruction may take a long time, it will be too late to repent.

Heed the warning from His Son:
“Strive to enter through the narrow door; for many, I tell you, will seek to enter and will not be able. “Once the head of the house gets up and shuts the door, and you begin standing outside and knocking on the door, saying, ‘Lord, open up to us!’ and He then will answer and say to you, ‘I do not know where you are from.’ "(Luk 13:24-25)