While preparing for changes to possible enemy capabilities is wise, these carrier-sinking wonder weapons have yet to actually demonstrate they will perform as advertised.
During the Falklands War the British lost six ships to the Argentinian air force, not exactly a military powerhouse. Four of the six were warships (destroyers and frigates). Analysts say losses would have been much worse if not for the many UXBs dropped by the Argentinians. Other ships were damaged.
The losses and threat of further losses forced the British navy to alter its operations in such a way that it was unable to provide its full support to ground operations.
If a third rate power like Argentine can pull that off I would think that someone like China, with its greater resources, could pose a serious threat to US carriers.
Besides, you don't need to sink a carrier to render it combat ineffective. Heck, dropping a crate of nuts and bolts on the deck would render it inoperable for quite a while as the crew is forced to walk the deck to clear the debris before air ops can resume! :-) In the case of China, they could also attack our navy by simply not funding it or supplying it.
Our military is extremely powerful in that it is lethal against asymmetric adversaries, but also extremely fragile, inefficient, and it lacks durability.
Strategic materials and resources (e.g. raw materials for gear and the cash to sustain it) are provided by potential adversaries such as China. We Americans love our big, expensive military but we're not willing to pay for it.
We have fought two major wars over the last decade resulting in two strategic defeats against guys with nothing more advanced than home made bombs, AK-47s, and RPGs, weapons which were essentially in use at the end of WWII. They lacked advanced missiles, MBTs, APCs, warships, or any other serious, heavy military gear.
Iran controls Iraq and Afghanistan is controlled by drug lords in the central government and the Taliban in the hinterlands. That happened despite our soldiers and marines winning every tactical fight.
The reasons for our inefficient and fragile military is a bipartisan issue that wanders into Blue Fez territory.