With the demise of the Soviet navy the only threat to the world's oceans the U.S. Navy is justifying more submarines on their ability to collect intelligence. It's also limited to collection in coastal regions. The money saved by truncating production of the Virginia-class would buy many intelligence satellites and manned and unmanned reconnaissance aircraft, which do not face the limitations of the submarine. With a negligible open ocean threat, no replacement for the Virginia-class is needed now, and the submarine fleet can be reduced in size. The DD-21 destroyer also should be scrapped.
Marines suffer from insufficient fire-support from the sea.
But they need high volume, suppressive gunfire to keep the enemy forces in their foxholes. Instead, the DD-21 reflecting the Navy's priority of deep strike is a missile ship with a couple of ancillary guns. Also, in a time of uncertain threats and constrained resources for defense, the Navy already has thousands of VLS tubes and should buy only versatile multi-mission ships rather than ships optimized for a narrowly focused mission. In the Gulf War, no scout helicopters were used with Apache heavy attack helicopters. If a scout aircraft is needed in the future, unmanned aerial vehicles might be more effective and would not put pilots' lives at risk.