There is a cost to produce something based on raw materials and then the possible price you can charge from the customer based on demand and supply.

The term Value is pretty vague here. Its more of a perceived value so its hard to put a number against it, there is no direct way to translate it to something more concrete.

May be bit orthogonal, one way I can think of it is to map to physical needs like clothing, housing, food and medicine?

It is really only the perceived value which matters to a business - that's the value at which you can sell or replace your asset on the market. Offers above that price, you sell (and replace if needed). Offers below that price, you don't.

If it costs more to produce (and sell) the asset than you can sell it for, you're losing money and assets go down. If it costs the same, then in this example the net change in S&P assets would be zero.