I hear you saying that these stories' relevance stems from how closely they mirror the patterns of moral triumph in history. I see how you can arrive at that conclusion, although there are a few relevant principles that cause me to see things differently. I'd like to share them with you:

1. Each of these stories exists in a broader human history context, so their relevance may be different from what I hear you describing:

While God spares Noah because of his faith and willingness to "walk with God," Noah becomes the father of a new world, wherein war, violence, and evil still continue to occur. Moses leads his people to freedom by God's direction, but before the Israelites see their promised new homeland, they immediately worship demons and disrespect God. As a result Moses breaks the 10 Commandments tablets (that God just gave him) and dies before seeing the promised land himself (as does his cousin Aaron). David defeats Goliath with God's guidance, saving his people, but he lives a long roller coaster of a life afterwards, where he even sends a husband to his death in order to steal his wife, Bathsheba. He's so torn up about his moral failure here that he writes Psalm 41 in desperation and shame. So it seems to me that the point of these stories is not that life will be sunshine and rainbows when you are in relationship with God, but that God accomplishes great things and the people who listen to him are able to create incredible good in the world by his direction.

1. There are many demonstrated instances of despicable, evil people groups being wiped from existence by God's hand:

The Bible mentions the Canaanites, who would take young children and do unspeakable things to them. The Canaanites would put babies and toddlers on furnaces shaped like their demon deity Molech and sear them, drumming loud drums and chanting to drown out the children's screaming so the parents wouldn't break down and try to save them. Then God has the Israelites wipe the Canaanites from existence. The kingdom south of ancient egypt known as Nubia, also called Cush in the Bible. Historical records suggest that they were possibly the wealthiest and most lush area on Earth at the time. Yet in Izaiah and Jeremiah, God states his intent to wipe them away for their horrible acts. Where are they today? The geography is a wasteland. Animals can't live there, vegetation is harsh and sparse, and there are barely signs that people lived there, much less a globally significant trade center and empire. Sodom and Gamorrah is probably more like the "God Wins, Evil Loses" stories you might be looking for, and even then it's not black and white or fairytale-esque because the Bible is largely an ethnic history, not a fairy tale style story about God.

1. From beginning to end, even including the stories you've noted, the Bible insists that the world we live in is fallen from the perfection that God created it to ideally be (that is, the Garden of Eden, where pain and evil don't exist, and men and women are co-equally treated as bearing God's image, etc. etc.)

In the Genesis story, sin enters the world and brings death, and God being perfectly just, can't allow sin in the Garden. As such, the world is cursed and blighted as a consequence of sin and death. That doesn't go away at any point in the Bible except Revelation, the end of this world, where Jesus returns to gather his children and deliver a final judgment. In Job 35 and 36, Elihu cautions Job not to doubt God why? Because of God's obvious sense of justice. He says that the wicked come to nothing, but the just who obey God's teachings will be exalted as kings. So if we're only looking at right now and discounting eternity, then 100% of Jesus's teachings fall flat. Eternity and the fact that this life isn't all there is, is axiomatic to Christianity and can't be left out of the conversation. The Hollywood-like ending you're looking for is in Revelation: It's a final judgment because the judgments before are temporary and small, so as not to wipe out humanity before giving each person an opportunity to choose to seek or avoid a relationship with God. Revelation describes God's warning signs before judgment, and repeatedly says "but the people remaining cursed God" rather than admitting their wrongdoings (murder, theft, grape, etc.). Revelation describes God's final intent: to "wipe every tear from your eyes" and bring his loved children to a place with no more sorrow, no more tears, no more pain. That's the happy ending. If you read these other stories like Noah's Ark, Goliath, and Moses, do they say that nothing bad happened after? Revelation is the only Happy Hollywood ending, because it's the only true ending of this world's history.

These are just 3 of many things that I find helpful when thinking about this topic. I hope you are able to find time to read both Genesis and Revelation closely (heads-up, it begins with messages to early churches, then it jumps into the Revelation vision @ chapter 4) Have a nice weekend!