I once asked my father, why for such a small population does New Zealand seem to have a disproportionate amount of innovative and groundbreaking engineers, particularly in the automotive realm (e.g. Bruce McLaren, Burt Monroe, John Britten, etc).
Even dad (who is a humble fitter and turner by trade) and a friend built a mid-engine, tube steel frame sports car from scratch (not a kit) in the '70s because they wanted one. Due to location and distance, in NZ you simply couldn’t buy what you wanted, like you could in the US or Europe… you had to make it yourself.
If you want something, you build it yourself, is something Kiwis have always done. I’m guessing that Glyn Powell upon realising that parts were no longer available just said “well I’ll have to build them myself won’t I”.