> A metaphor compares two things similar from a certain aspect
When I said "the metaphor compares two similar thing" I didn't mean metaphors in general, I meant your metaphor specifically compares two things that are similar. The relevant differences between NY and the moon do not exist between NY and Illinois.
> For the same reasons that it's needed elsewhere
Metaphors are often of dubious value. They can be used to clarify unfamiliar situation, where the bounds of the metaphor are clear; or, perhaps as in this case, encourage similar thinking about two related concepts.
But you provided a metaphor here without providing clarity on what the point was. When I think "why would I build a city in Illinois, when there already one in NY", none of the answers I come up with apply equally to the moon. e.g. land is cheaper/convenient (not on the moon), the scenery is better (maybe true, but not to outweight other more pressing concerns) etc.
When I said "the metaphor compares two similar thing" I didn't mean metaphors in general, I meant your metaphor specifically compares two things that are similar. The relevant differences between NY and the moon do not exist between NY and Illinois.
> For the same reasons that it's needed elsewhere
Metaphors are often of dubious value. They can be used to clarify unfamiliar situation, where the bounds of the metaphor are clear; or, perhaps as in this case, encourage similar thinking about two related concepts.
But you provided a metaphor here without providing clarity on what the point was. When I think "why would I build a city in Illinois, when there already one in NY", none of the answers I come up with apply equally to the moon. e.g. land is cheaper/convenient (not on the moon), the scenery is better (maybe true, but not to outweight other more pressing concerns) etc.