Just musing:
If only all that creativity and those budgets could be used to solve other problems.
Even with no war going on, and no acute necessity of creativity for defence, we appear to be afraid enough all the time (or manipulated into thinking military expenditure is important) to spend many moneys on development of weaponry, and somehow we are at our most creative when that development involves killing other people.
If you can kick-start an economy by, for instance, killing many Germans, why can't you kick-start an economy by solving some famine problems here and there? Why does all that creativity go into (para-)military development even when there is no acute need for it, ie. no current circumstances dictate it?
I believe is because of prevailing over one another. Social darwinism. In much the same way we prefer our children over others.
@kyriacos reply I believe is the root of the answer to your question. However, another big factor is that war time is when DAPRA and other government agencies/budgets grow exponentially. Being a mechanical engineer myself, I know that creativity and invention hinges on one factor - money, support, and budget. War time budgets are way larger than peace time budgets (and for good reason if you ask me).
So yes, again, we are back to the love of money issue.