0.75m aerial imagery from 2005-2011: https://data.linz.govt.nz/layer/51934-southland-075m-rural-a...
I'm not sure what you think you're seeing in that picture, but it sounds like you've been listening to too many conspiracy nuts. Not many people live in or go to Stewart Island, so the demand for satellite/aerial imagery is pretty low. It's hardly surprising it's not as recent or accurate as, say, this 7.5cm imagery of Auckland: https://data.linz.govt.nz/layer/95497-auckland-0075m-urban-a...