The Only Option

In Parshat Noach G-d decides to destroy the entire world with a flood and repopulate the world through Noach and his family. This decision confuses me. If a kid makes a model of something for school and found something wrong with it and wanted to just destrop it and start over, a mother would usually say 'no, don't mess it up, we can fix it!" I'm not trying to compare G-d to a child, but the decision making is similar. Why should G-d feel the need to destroy a world when He could fix it. Punish the people maybe or find a way to show them that He is G-d and if they don't obide by his rules, they will be wiped out. There must be other options other than just destoying the whole world, right?

So, I don't know the exact answer, but this is what I came up with:

Adam and Chava. The first people to be created. Also, the first people to commit a sin. So, what was G-d's decision there? Punishment. You would think after these harsh punishments, everyone would follow G-d's commandments and not sin. But, it's only one generation later that Kayin kills his G-d fearing brother, Havel, and decides not to do Teshuva and is punished. Already, out of the first four people on this Earth, three have been punished, and the fourth was killed by his immoral brother. The world is not turning out the way G-d had planned. Now, there are many immoral, unethical people commiting sins, mating with animals, and not fearing G-d. Shet (Adam and Chava's third son) has a son named Noach. Noach is not on the same level as Avraham or Moshe, but in his times he is the most moral and G-d fearing man. This is when G-d makes his decision. Get rid of the bad people and repopulate the world through the only G0d fearing, ethical man, Noach. G-d knows by now that punishment might help a little in one generation, but will not help in the long run as we see with Adam and Chava and their immoral son Kayin. By now G-d has realized that yes, man is inclined to sin. Man cannot be expected to know how to act. Therefore, G-d must give them written instructions on how to act in a moral and ethical way. But, it is now too late. The people are already too corrupt to follow any set of instructions G-d will give them. Noach, unlike Avraham does not try to teach the people about G-d. There seems to be no chance to turn these people around. The only option left is to start new. Wipe these people out, repopulate, and give them the 7 Mitzvot Bnei Noach.