You don’t get ransom if your cargo is toast and your crew is bleeding. I don’t think there is any danger of the pirates “escalating” the violence . . . especially the pirate who was killed.
Just one possibility. The pirates have the resources to escalate. Whether or not they will, and whether or not piracy will remain profitable if they do escalate remain to be determined.
You’re right: I don’t know how they could move the cargoes and ships if they couldn’t ransom them. But given their organization, I wouldn’t be surprised if they started hiring brokers...