The $10 Quadrillion figure is total baloney. You can't just take the current value and extrapolate, because the price would fall as the supply rises.
It is true that if you dumped all that metal on the market, its price would plummet. But that doesn't actually reduce the value of that metal.
Price and value are two different things. The value of that metal is described by the stuff that you can build from it: bridges, towers, spacecraft, etc. That value doesn't actually change by having more of the stuff available. To understand the value of something, you look at the price of it.
Price isn't a constant scale, and it changes over time. There are two different prices that are important here. To understand the value of that metal, looking at its current price is actually quite a good measure: that is how much better we would be off, in current dollars, if we got all that metal. The future price of that metal tells you its value on a different scale, the scale of a society where everybody is much richer because a dollar buys much more stuff.
So, if you want to understand the value of that metal, look at it in current prices. The difference between how much that metal would (hypothetically) cost under current prices and how much it will cost once it's available and prices have plummeted is a measure of how much richer the world has become by making all that metal available.