  We provide a theoretical framework to understand when firms may benefit from
exploiting previously abandoned technologies and brands. We model for the long
run process of innovation, allowing for sustainable diversity and comebacks of
old brands and technologies. We present two extensions to the logistic and
Lotka-Volterra equations, which describe the diffusion of an innovation. First,
we extend the short-term competition to a long-term process characterized by a
sequence of innovations and substitutions. Second, by allowing the
substitutions to be incomplete, we extend the one-dimensional process to a
tree-form multidimensional one featuring diversification throughout the
long-term development.
