Thanks Matt for the kind reference to Kiwis.
American cars were relatively common in NZ pre WWII, but English cars predominated immediately post war due to our trading arrangements with Britain.
So 'new' American cars became a rarity; and therefore were much sought after.
When something is rare; it becomes almost a fixation to either own one or to find out as much as possible about them...hence the Kiwi fascination with American cars and road trips.

(That's not the full story; rather a brief synopsis...obviously there are many other factors that have to be taken into consideration.)

And as for your fellow citizens not showing the interest that 'foreigners' do?
It's the same the whole world over mate...we've got a bloody gorgeous and relatively easily climbed mountain right in our own back yard. It's the first thing I see every morning.
Have I ever climbed it?
Nah...I got half-way up once to Tahurangi Hut on the Stratford side, and as far up as Kahui Hut on this side...and both times turned around and went home.
So mea culpa for not seeing my own country before I left home!