it turns out that there was a massive nuclear world war in the mid-21st century that did massive damage to the world.

By the Trek timeline, that war literally starts next year and runs for thirty years. Mankind only starts to pull it’s head out of it’s ass because of first contact with the Vulcans, and that only happens because they happened to have a ship in the system when the guy building the first experimental warp engine takes it on it’s first successful test flight in 2063.