Been reading this thread with sadness having just come back from three weeks driving in NZ, my observations made me think something like that was inevitable.
There did appear to be a large number of cyclists on the roads, many of them were less than experienced cyclists, just young people who fancied the idea. I chatted to one guy headed north up South Island that had just hired a bike and bungeed his rucksack on the rack. He was sort of enjoying himself, I neglected to mention the climbs he was going to hit the next day.
There are numerous reasons I felt NZ cycling would be sub-optimal.
1) Roads. As the state publicity tries to hammer home, NZ roads are different. There are so few of them, so no options to take quiet roads. They are almost universally two lane, sometimes with adequate provision for cycling, sometimes not. (Really weird to see cycle lanes on what we would call motorways). Flip side, outside of the main drags the roads are SO quiet and SO beautiful you really really really want to be on your bike. The roads are all relatively recently cut, so tend to be adapted to motor vehicles with steep grades, rather than donkey tracks, bends also have a different character than you would find in most other countries, nearest I've seen is in Corsica, these not only make it harder to cycle, although not fundamentally bad they pose a challenge to drivers, leading to ....
2) Quality of driving. That's a mixed bag actually. But there are a lot of drivers who don't appear to be able to deal with traffic. Lot who seem to have issues with roads. Then you have commercial vehicles, which are on the same single track roads, some driven ok, some are crap. Then you have old farts like me banging around in RVs, without much road sense, they come from all over with varying abilities at the best of times. Apparently driving on the wrong side is a common accident cause in NZ. From the perspective of the driver generally people seem to be quite good to cyclists, but from the perspective of cyclists the percentage of bad drivers pose a level of unpleasantness that is going to make life tough. I chatted to a few cyclists along the way and that seems to be quite common.
3) Weather. It rains there, especially on the west coast of South Island. I wouldn't want to be caught on the road in that sort of downpour with those sort of drivers.