I'm just saying.Nonsense. The absence of evidence isn't evidence of absence. The fact that the Sailor wasn't an example background in this document doesn't mean that it won't be one in the 2024 PHB.
Sailors can sail boats, and making a Custom Sailor Background allows you to take Sea Vehicle Proficiency.
I'd give Sailors Sea Vehicle Profieciency before Navigator tool proficency.
With 5e as an example, we can easily realizes that designers can forget to add basic stuff if no one reminds them.