All ships can't be these multi-role behemoths we're so accustomed to in Halo. Carriers are needed to provide a combat air patrol for the fleet and close air support for landing and occupation forces, as well as command facilities for a task force. Cruisers for command functions, air defense of the fleet and self-sustaining long-range patrols. Destroyers for ship-to-ship fighting and many other combat-related duties. Frigates and corvettes for local patrol, landing support, and defense against stealth vessels.

The Covenant and the UNSC may not have faced a worthy space-faring adversary separate of their experiences during the Great War, but these sorts of ships are nonetheless vital against a wide array of threats they may encounter. That's why you see the United States possessing a large fleet of carriers, cruisers, destroyers, and landing vessels, as well as frigates, corvettes, and smaller vessels. Our Fleet is both expeditionary focused and forward-deployed and local, able to function in the traditional naval battles seen in the past, and in low-intensity patrols on their own shores and against littoral threats.