Most of us probably have a job description with a list of duties or something along those lines. But I've come to realize that certain circumstances notwithstanding (unions, etc), it's just a farce. Most people's actual job is to keep their boss happy, which you can do by helping them with their job, which is to keep their boss happy.<p>OP's job duties were fulfilled correctly until they weren't. The boss was happy because he didn't have to pay for backups and when it became unfeasible to keep the boss happy (data loss), OP recognized his job had become impossible and he quit.
Replace "disaster recovery" with "incident response" and this is too familiar. The thing some of you may not know is with managment like that, even if the sysadmin found a free backup solution, management would double down on not needing backups especially since the data loss was not complete and they came back up so fast even after a major hurricane. If he tried to convince them to pay for a consultant to tell them the same thing, things might have been different.
When making DR recommendations I have straight up told my boss "Under current circumstances, if this happens, my plan is to quit". Then I tell him what I think needs to happen for me to feel good enough about it I wouldn't quit if that happened.
This seems like a reasonable response to unreasonable circumstances. I am not sure there are other options that allow folks to maintain their professionalism and to prevent management's intentional lack of planning from becoming a personal emergency.