Underway and SKT basically stated the technical reasons that prevent such landings on a destroyer/frigate helicopter deck (though, I am sure in case of flying emergency, a F-35B pilot would probably prefer to attempt it rather than ditch in the water). But they did not address the tactical reasons, which come down to: While a frigate with a tail and a helicopter makes a powerful ASW weapon, what useful thing could a frigate carrying a single F-35B do, i.e. how much of a threat to any one would it constitute. You would need to use in concerted effort a fleet of forty destroyers and frigates to give yourself the projection/warfighting power of a single aircraft carrier (and I am not talking US super-carriers here but the more modest European/Japanese/Indian ones). Much easier and cheaper to have a carrier strike group.