  Demand-pull and technology-push are linked to an empirical two-layer
network-based on coupled cross-industrial input-output (IO) and patent citation
links among 155 4-digit (NAICS) US-industries in 1976-2006 to study the
evolution of industry hierarchies and link formation. Both layers co-evolve,
but differently: The patent network became denser and increasingly skewed,
while market hierarchies are balanced and sluggish in change. Industries became
more similar by patent citations, but less by IO linkages. Having similar R&D
capabilities as other big industries is positively related to innovation and
growth, but relying on the same market inputs is unfavorable but may incite
industries to explore other technological pathways. A tentative interpretation
is the non-rivalry of intangible knowledge. This may strengthen existing R&D
trajectories. Growth in the market is constrained by competition and market
pressure may trigger a re-direction in both layers. This work is limited by its
reliance on endogenously evolving classifications.
