From the article, it seems that container losses don't generally happen one at a time, but rather you have some event where a ship loses hundreds at once. I guess if you're quick maybe you could get a ship in and scoop them up before they sink, but in order to save more than a few you'd need a big ship and most of the time you'd just be sitting around waiting for the next container loss event, and the ship would sit idle for months or years.

I'm assuming that if it sinks in deep water it's gone, but even there maybe there's an opportunity to salvage containers off the sea floor with the right equipment. Probably not worthwhile economically, but who knows?

Maybe the best case for this could be made for ships that normally at sea doing other things to be ready to divert from their ordinary tasks to collect containers if they don't have anything more pressing. (Coast Guard ships or Navy support vessels perhaps?)