For an evolutionary system, continuing development is needed just in order to maintain its fitness relative to the systems it is co-evolving with.
The Red Queen as a principle was proposed by the evolutionary biologist L. van Valen in 1973 and is based on the observation to Alice by the Red Queen in Lewis Carroll's "Through the Looking Glass".
Since every improvement in one species will lead to a selective advantage for that species, variation will normally continuously lead to increases in fitness in one species or another. However, since in general different species are coevolving, improvement in one species implies that it will get a competitive advantage on the other species, and thus be able to capture a larger share of the resources available to all. This means that fitness increase in one evolutionary system will tend to lead to fitness decrease in another system. The only way that a species involved in a competition can maintain its fitness relative to the others is by in turn improving its design.