The difference is that NZ had other trade arrangements in place that were not determined by association with a custom's union.
So life outside the EU exists, countries can negotiate their own trade deals, how novel. And here I thought the UK was completely reliant on the benevolence of Brussels. You have effectively defeated your own argument by acknowledging that life exists outside of the EU.
The UK will literally be the only country in the world to suddenly have no trade agreements with anyone if it has no exit agreement with the EU. It will be the only country in the world to trade solely on WTO rules, which no other nation does for a good reason.
Neither one of these is true. The world does not revolve around the EU, the two largest economies on the planet aren't involved with the EU and make their own trade agreements. Last I checked neither the US nor China was beholden to anything out of Brussels and both have their own trade deals with various nations in the world.
In non-BBC worthy news, the US has been negotiating it's own trade agreement with the UK for months now. I can't imagine China isn't doing the same thing, the same it does with every other major world power.
My comment wasn't about you living in New Zealand, it was about pointing out that the UK will not suddenly collapse when it gets rid of the EU. The EU is merely a small part of a much larger world, a part that doesn't include the country your living in. As someone living in New Zealand, who is not part of the EU, by your own argument you should be living in squalor and post-apocalyptic mad max conditions.