Gold could fall like a rock any day imo due to asteroid mining.
And that's easier than you might think. All the gold mined on earth fits in a cube with 22m sides - any asteroid could easily double the supply. And the mining process would just be stiring an asteroid slowly to fall into the desert.
But it gets even easier than that: Markets are forward pricing. All it takes is Elon tweeting that he wants to do it and markets will price that in.