Vault is purely fictional. The story and characters were made up by the author's imagination. There's no connection to any real-life incidents or people.
The Vault is more likely to be a product of imagination. Usually, such elements are crafted to build an engaging narrative rather than being based on real events. There might be some inspiration drawn from real-life situations, but it's not a direct reflection of a true story.
Vault 21 was a social experiment vault. It was centered around a casino. The people there had a unique society based on gambling and entertainment. In the game, the player can interact with the remnants of this vault society and learn about their past and how they functioned.
I'm not sure specifically which 'the vault' you are referring to. There could be many things named 'the vault'. It might be a vault in a bank, a secret vault in a story, or something else. Without more context, it's hard to tell the real story.
The 'vault true story' could be about many things. It might be about a real - life event related to a vault, like a bank vault robbery or the discovery of a hidden vault with something valuable inside. Without more context, it's hard to say exactly.