Most Scandinavian countries, with much more robust economies and similar populations and land areas, do not rely on roading for transit and shipping.
NZ's sealed to unsealed is currently running at a ratio of about 55% to 45% in favour of sealed roads.
Until very recently Sweden's major highway was unsealed outside of it's major cities, hence the number of stunning rally drivers that emanate from the region. Similarly Finland and Norway have a much greater ratio in favour of unsealed roads to sealed roads than NZ. I have Norwegian relatives who are constantly surprised by the depth, breadth, and quality of NZ roads, and our comparative lack of rail and shipping.
I repeat: The roads are not to blame. If they were all gravel, it would still not be the road's fault. It's the nut behind the wheel/handlebars.
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