Core industries is how we won WWII.
We could not do it today.
Those factories that were repurposed for making guns, tanks and other weapons are gone.
In an age of ICBMs, satellites, and a permanent human presence in orbit, the idea that mass-producing military hardware like tanks and ships will have any role in a major armed conflict is silly.
The only traditional military hardware that will matter will be the stuff that exists on the day the shooting starts. This isn't the 1940s. The entire surface fleets of nations could be sunk within hours, and all the steel production capacity in the history of the world couldn't keep up with that rate of attrition.