God has CHOSEN not to. After 370 sweaty and smelly days aboard the ark, faithful Noah disembarked and immediately offered a sacrifice to God, a significant sacrifice of 1/14th of the remaining clean animals and birds on the planet. This act of love and submission, perhaps second in importance only to Jesus' decision in the garden of Gethsemane, leads to a change in God's heart. In experiencing love from Noah, God remembers that free will is the necessary price of that love, and the consequence of free will, is that evil will abound. So God chooses a different strategy than destruction by flood to combat evil and encourage righteousness – first, he will choose one family on earth as a role model, headed by Abraham, instructing them on how to live in God's favour. And second, from a girl in this family named Mary, he will beget a son, who will sacrifice his life on the cross so that the evil acts of humanity can be forgiven. From now on, God gives Noah a promise NOT to destroy the earth with a flood – and will instead implement the strategy his son Jesus elaborates in a parable, “in gathering the weeds you would uproot the wheat along with them. Let both of them grow together until the harvest, and at harvest time I will tell the reapers, Collect the weeds first and bind them in bundles to be burned, but gather the wheat into my barn.” This promise from God is a fact in which we and all of God's creatures can rejoice, each time we see the symbol of the rainbow in the clouds.
And in response to Noah's love, God grants to evil humanity, free reign to be fruitful and multiply, PLUS, God grants humanity dominion over the earth and all of its species.
We are blessed to live on a planet God has made to be reliable - we can count on seedtime and harvest, cold and heat, summer and winter, day and night. And we are blessed to live on a planet where God has given his son for our benefit, so that we can turn to him and receive eternal life.
Heavenly Father, purge from us all of the evil in our hearts, and enable us to respond to you in love. Give us strength and opportunity to oppose the wickedness, corruption and violence happening around us, in Jesus name.... Amen.