The absolute worst case is that it's not advantageous/useful at all in the next war to have the capability, but it wouldn't harm you at all if you do have it, it just wouldn't be useful. In every other case, from the worst case all the way up the continuum to the best case, having the capability is beneficial to varying levels of degree.

How many billions have you spent propping up useless industries in the years before the war though? What capacities could have been built with those billions otherwise?