[Enginerrrd]

I think if we really looked at it, it likely comes from fishing where "to land" a fish means to succeed in quite literally getting it onto land from the water. But we use it as "to successfully get" (something typically uncertain) in many other contexts.

[chrisweekly]

though you can "land" a fish while still on your boat.

disclaimer: beyond pedantic, but 100% appropriate given the topic is NLP and idioms

[Enginerrrd]

Sure, although what is a boat but an island to a fish?