Is it true that INZ exist to decline visa applications?

It sounds overly cynical but this is more or less true. Any country's immigration department manages who can and cannot come into the country and for those who can enter, control for how long, if they can work, study, etc. So it is fair to say that INZ's actual role is to restrict entry rather than to facilitate entry.

Restricting entry doesn't necessarily mean declining every application, but it does mean that the purpose of the application is to prove that the applicant meets the criteria and so does not deserve to be declined. Some clients misunderstand that INZ is a service based organisation who want people to visit New Zealand. This is an easy mistake to make because the website sure looks like this is the case, but experience and logic shows that it is not.

Fee increases as well may make applicants think they are paying a lot, so they should expect a good service in return, this is not the case. The Government sees the immigration fees and levies as only paying for running the system, there is no promise of service or quality, as well as there is no perception that you are paying for the visa. The INZ fee is to pay for the assessment, not for the visa itself.

We do every application from the starting point that INZ will be assessing it to see how it can be declined, so we make it in such a way to clearly show why it should not be declined. Applications that fail usually do so because there is either a clear reason why the applicant does not meet the specific criteria of the visa, or there is no compelling evidence to convince the assessing officer that they do. 

I think everyone's experience with INZ would improve a lot if they thought of visa applications and INZ in this way.