In the event F35B is binned, there is a binary choice. There are no more STOVL options, so the choice is between converting QEC and PoW to CTOL ops, or getting out of carrier (and probably power projection) ops for good.
If the choice is the latter, sell or scrap, endex.
If the choice is the former, then the ships are convertible, as planned, which is something you wouldn't have with a smaller ship. It just costs money - whether that money is actually as much as presented when the back to STOVL deision was made, is likely to come into sharp focus. Whether the aircraft option is F18E, Rafale or F35C is somewhat irrelevant.
As for carrier vulnerability, isn't it strange that no-one mentions what a DF21 - allegedly capable of being guided to a 300m x 70m moving target - might do to a fixed installation where runway intersections, fuel farms, bomb dumps etc would be far easier to target and when hit be just as easily damaged? One suspects a ballistic HE warhead travelling at several hundred metres per second is likely to cause damage far in excess of Durandal-type cratering munitions and way beyond your normal runway repair capabilities.