You simply don't understand how shipbuilding works. Regardless of urgency or funding it takes years to scale up production. By the time that happened, any possible large-scale conflict between advanced near-peer adversaries would be long over. Modern weapons are just too accurate and destructive to make long wars of attrition possible any more. Within a few months one side or the other would suffer crippling losses and then have to decide between surrendering or going out in a blaze of nukes.