Creative Destruction
A term coined in 1942 by Joseph Schumpeter in his work, Capitalism, Socialism and Democracy, to denote a "process of industrial mutation that incessantly revolutionizes the economic structure from within, incessantly destroying the old one, incessantly creating a new one."
Investopedia Commentary
In other words, creative destruction occurs when something new kills an old thing. A great example of this is personal computers. The industry, led by Microsoft and Intel, destroyed many mainframe computer companies--but in doing so, entrepreneurs created one of the most important inventions of this century.
Schumpeter goes so far as to say that the "process of Creative Destruction is the essential fact about capitalism." Unfortunately, while a great concept, this became one of the most overused buzzwords of the dotcom boom (and bust), with nearly every technology CEO talking about how creative destruction would replace the old economy with the new.
See also: Bubble, Dot-com, Economy, New Economy, New Paradigm, Old Economy