If orange trees grew all over the country, you couldn't sell oranges. Do you understand that? So, all our decision making is based upon scarcity or the availability of resources. If we have a shortage of any kind of resource, we put all the labs to work on making substitute materials. People always worry about 'What if we run out of a certain material?', but we have enough technology today to make thousands of different substitutes.
The long bitter years of the Cold War are over. America and her allies have won; totally, decisively, and overwhelmingly. . . . So thank you SAC. Job well done. Enjoy your retirement.