The linear unidirectional nature of supplies & demands is fast getting transformed into bidirectional complex web if 'prosumers'. This is driven by the closeloop interaction of technology & business models - disruptive technologies create new business models & markets which in turn create opportunities for innovation & new technology.
The concept of additive data points of supplies & demands leading to aggregated curves suited the 20th century wherein the 'flows' were well behaved and directed one way.
Today, the scenario has changed - unless the theory of general equilibrium is relooked and modified, more bubbles may be building - only to collapse.
Who's the buyer & who the seller - they are no more static. The dynamics of movement of seller to buyer to seller... role needs to be quantified and thus the curves be augmented by adding time dimension to capture dynamics.