Everyone gets a cap these days. Loads of games, 8 subs, rotation. And from an NZ pov constant refresh as players leave for overseas club rugby rather than hanging around until their 30s.
The unlucky ones I have seen were from the amateur days. Most unlucky was Duane Monkley, the Waikato openside of the 1990s. He had Michael Jones and then Josh Kronfeld in his position and at other times selectors chose others when Jones was injured or unavailable.
Marty Brooke would be the next best NZ domestic player I saw go uncapped. Auckland lock of late 80s and early 90s, Zinzan and Robin's older brother. We chose some much worse but a few cm taller players instead, although they were just midweek all blacks anyway (Tregaskis etc)