Materials scienctists employ theory to simulate a physically accurate environment for their search of new materials. They never aim to develop theory any further, and more importantly they cannot, since their simulations are unable to produce results that contradict the theory they are based on.
On the other hand, good knowledge of the theory and its potential weaknesess and strengths is required in order to accurately produce and interpret results from simulations. This close relationsip of material scientists with theory creates the misconception that they work on further developing theory rather than just employing it as a tool.