It is not our only space venture. Our universities are churning out aerospace engineers. It annoys STEM academics that the space industries keeps "poaching" the best grad students.
To the best of my knowledge, the company is not a strategic priority for New Zealand, we do not absolutely need to launch our own satellites. It is purely a commercial venture. They had no choice but to make it a joint effort.
If it was not a joint effort they would have far fewer customers and a extremely limited supply chain.
Quite a while ago when I met an MP who seemed interested in space. I asked if anything could be done to keep/inceltivize future space ventures fully on-shore. They shrugged their shoulders and said no.