The first is that the governments were willing to allocate vast amounts of money and resources for the development of new materials that would give them advantages over the opponents.

During normal market conditions, it would have been impossible to secure so much money for research whose results were uncertain to generate financial profits.

The second reason is that during wars the global commerce routes were perturbed, so many materials that normally were cheap and easily available became expensive or impossible to procure, which could block the production or the usage of certain kinds of weapons and military equipment.

Therefore it became necessary to find substitute materials, which was the origin of many research projects, e.g. nylon instead of silk, synthetic elastomers instead of natural rubber, synthetic gasoline instead of gasoline extracted from fossil oil and so on.