While much of Rocket Lab’s team is still based in New Zealand, they are now a US-based company and their Neutron reusable medium-lift rocket will be built in the US and launch from the Mid-Atlantic Regional Spaceport (MARS) in Virginia.
As far as I know they do not have any plans to launch reusable rockets from New Zealand.
Its latitude is really not optimal for anything other than polar orbits and it’s too far from any potential customers which would increase the cost considerably.
Not only do they have plans to, they have already launched multiple commercial missions on their Electron rocket from NZ!
> "Its latitude is really not optimal for anything other than polar orbits"
I don't think latitude is the major reason. Rocket Lab's Ahuriri Point launch site is at about 39.2 deg S, not that much different to the Wallops Island, Virginia site at 37.8 deg N. Baikonur Cosmodrome, by comparison, is at 46 deg N!
> "it’s too far from any potential customers which would increase the cost considerably."
Yeah, this is the real issue.
And the distance doesn't really matter much. Its not that expensive.
The reason to go the the US, is US military launch more then anything else.