So 150-200 times 2-4 Mbps is 300-800Mbps for the whole country.
There are about 5 million people in New Zealand. About 13 percent are rural. Let's say 30% of those are in areas where this would be useful, or about 4%. 200,000 people, and about half are the age and temperament to have a cellphone. Let's say they're using this data 1% of the time. That's 1000 people at a time, on average. So the useful data rate per active person is about 800kbps. That's not great, but still usable even for 240-360p video streaming, music streaming, navigation, normal web stuff. About 2.5 Gigabytes per month per 100,000 subscribers (although due to time of day, etc, that's probably more like a usable 1-1.5GB per month). For casual users with wifi at home, that's not that bad. I think my wife uses about that much or less.
Interesting point about total bandwidth accross NZ, but I think your calculations are a little optimistic. Rural NZ is not distributed evenly. The only calculation that matters if how many people per beam/cell, and how good the performance is on any given cellular device. The device may limit the performance regardless of other users.
If there are 10 people (0.5 people per sq km) in a given 50km2 beam, then they could at best get 200-400kbs.
Even a high country shepard is likely to be in a 50km2 block with many other people working at the same station.
Anyone on a popular walking track in the middle of nowhere is also likely to be around other people.
I am sure 2-4mb is a starting point and doubling that would be possible.
I think pricing will determine how useful it is. If you take the 2% of the population in the 50% of the country that doesn't have terrestrial coverage then the bandwidth isn't really that bad - it's the same or better than other options in a comparable footprint or reasonable cost with the bonus it'd be on the same device you normally carry with you which auto switches back to high speed when you're in town.
