It’s unfortunate that many CA wineries use screwcaps only on their most inexpensive wines like a rosé or red blend. That just continues the American perception that screwcaps are cheaper (inferior).
Being at the end of the supply chain around the World for corks, NZ winemakers typically got rubbish corks in the 1990s and early 2000s (I heard of cork failure rates for premium wines in the 5-10% range, which obviously isn’t feasible). Between around 2001 and 2003 most premium NZ producers shifted entirely to Stelvin closures (some, for a while, went mostly screwcap, but bottled some wines with cork for the Asian market, however most have now abandoned this). So now, most of the top NZ wines are bottled under screwcap including Ata Rangi, Mt Difficulty SVs, Felton Road, Kumeu River, Neudorf etc etc. Screwcaps don’t seem to have affected their ability to export these wines.
Some top NZ producers, who could secure good quality corks, have however stayed with it (eg Te Mata, Stonyridge and Dry River) and some even went back to cork having done screwcap for a few years (eg Escarpment) or mix it up between screwcap and cork for different premium wines (eg Craggy Range).
The 2001-2003 screwcap closed NZ wines I’ve tasted have all shown as I would expect, showing ‘correct’ development under the screwcap. On the other hand, I’ve had many ‘shot’ cork closed NZ wines from the same era.
BTW, I believe that Laroche has now gone back to cork having a few years under screwcap, because they now believe that they can manage premox with their corks.