In 1980’s-1990’s there were a heap of high profile AW heroes running around the National League. Now there are none, and a club based league won’t change that.
Also back then there was virtually nil football on TV, and the internet didn’t exist.
Many football fans would nowadays rather spend their valuable spare time, watching their favourite European club team play in a high quality league with all the excitement that brings - through a high definition screen, than attend a much lower quality National League game in NZ live. Not saying it’s right, but it’s basically irreversible.
Same reason why ITM Cup rugby crowds are now poor. The All Blacks no longer play in that competition, and after a high quality Super Rugby Comp (and even that is suffering from a drop in live crowds) with all the stars, the average fan is suffering from “product fatigue”