They will most likely be mothballed until the worst has blown over.In the long run they are just delaying the inevitable, lack of service / support / spare parts will render all these Superyachts useless.
Once they reemerge there are plenty of places in the Indian and Pacific oceans to cruise and I'm sure they can find all the skilled trades in Asia if needed. Sooner or later they'll be welcomed back into the the Med and Caribbean.