You're seriously trying to play the "history" game with a Brit?
We have craft brewers with 300 years of history, never mind 30; we were importing hops for centuries before Columbus sailed. On a per-capita basis the UK has 5 breweries for every 3 in the US - the brewing thing runs deep here.
If by "craft" beer your mean "beer with US hops" then yes, obviously that began in the US. But at the same time there's a certain parochialism that comes when world-class produce is on your doorstep - you see it most clearly when you try to buy wine in France. The average French supermarket will have nothing but French wine, with just a few BMC-equivalents from overseas. Compare that with a British supermarket - not having much domestic wine production of our own, we're rather more open to cherrypicking the best worldwide, so you'll see claret next to California cabernet next to one from Coonawarra next to a wine from Uruguay or China. One doesn't really appreciate that "import" mindset until you go to a winegrowing country.
I guess with hops it's exacerbated by the fashion for high-terpenol beers, using US-type hops. So in the US, people just use the local ones and there's not much interest in paying import costs for foreign hops with lower terpenol content - I guess there's not much interest across the pond in hops like Jester and Ernest, whereas there's quite a lot of British brewers using them. And just generally, that old beer tradition means that there's still a lot of people brewing old-school beers - if the bulletin boards are any guide, a small majority of British homebrewers seem more interested in trad British bitters, which use British or European hops. So for instance, our online stores carry several Slovenian varieties, whereas you guys might get a generic "Styrian" if you're lucky - whereas we get a pretty decent selection of US hops.
Specifically on NZ - part of the deal of us joining the EEC/EU was that the Commonwealth countries lost their favoured trading status with the UK, which caused some upset at the time and has been one of the arguments of the Brexiteers. It's more just that cultural affinity of family etc links, and the import mindset I mentioned earlier.
Just to give you an idea, I've done a rough comparison of two British and two US stores, I've roughly deduped them but only quickly, so don't hold me to it! (another massive cultural difference is that our stores do roughly as many cones as pellets, I was amazed the way you guys only really do pellets, whereas ours will offer a choice of pellets and cones for the big varieties)
https://www.morebeer.com/category/beer-hops-brewing.html
https://www.northernbrewer.com/brew...s/pellet-hops?dir=asc&limit=72&order=name&p=1
https://www.brewuk.co.uk/ingredients/ingredientshops.html
https://www.themaltmiller.co.uk/product-category/ingredients/hops/
BrewUK has 13 NZ out of 106 total
Morebeer has 10 NZ out of ~99
Northern Brewer (no relation !) has 9 NZ out of 89
TMM has 9 NZ out of 85
I see no evidence of your hypothesis that the US gets "a better selection"! I'll admit that I was maybe biased because I tend to get my mainstream hops from BrewUK, and the pellet/cone thing inflates the overall numbers (it was 163 units in their hop list before I deduped it)
JFTR, this is the current BrewUK list :
Admiral, Ahtanum, Amarillo, Apollo, Aramis, Archer, Atlas, Aurora, Azacca, Beata, Belma, Bouclier, Bramling Cross, Bravo, Brewers Gold, Cascade, Cascade (NZ), Centennial, Challenger, Chinook, Citra, Cluster, Columbus, Comet, Crystal, Dana, Delta, Dr Rudi, Ekuanot, El Dorado, Endeavour, Epic, Ernest, Eureka, First Gold, Flyer, Fuggles, Galaxy, Galena, Glacier, Goldings (East Kent), Goldings (Worcester), Green Bullet, Hallertau Blanc, Hallertauer Hersbrucker, Hallertauer Mittelfruh, Huell Melon, Jarrylo, Jester, Junga, Kazbek, Liberty, Lubelski, Magnum, Mandarine Bavaria, Marynka, Minstrel®, Mosaic, Motueka, Mount Hood, Nelson Sauvin, Northdown, Northern Brewer, Nugget, NZ Kohatu, NZ Southern Cross, NZ Wakatu, Olicana, Pacific Gem, Pacific Jade, Pacifica, Pekko, Perle, Phoenix, Pilgrim, Pilot, Pioneer, Premiant, Progress, Rakau, Saaz, Saphir, Simcoe, Sladek, Sorachi Ace, Spalt Select, Sterling, Styrian Cardinal, Styrian Dragon, Styrian Goldings (Bobek), Styrian Goldings (Celeia), Styrian Goldings (Savijnski), Styrian Wolf, Summer, Summit, Sybilla, Target, Tettnang, Triskel, Vic Secret, Wai-iti, Waimea, Warrior, WGV, Willamette, Yellow Sub
[no connection with either BUK or TMM other than as an occasional customer]