The current NZFC format has worked for 15 years with a few tweaks, after the previous 15 years when they tried a dozen different formats and all of them failed for varying reasons. Why mess with success because of a temporary funding hiccup, especially when a plan for development/expansion was already in place.
Because it is impossible to call the current format and the majority of entities that take part in it a "success," for starters.
Compared to everything that was tried 1990-2004, it is a success. It pays not to have unrealistic expectations in NZ football..
As to the individual entities involved, isn't that what NZF's existing plan is meant to do - re-align the HandyPrem with the winter competition "gradually", rather than throwing it in the garbage and starting from scratch?
I honestly don't see any reason to believe that "Superclub 2.0" would be any better than the original version, just that some people have short memories. You have to explain what the "context... and reasons for change" would be - I can't see anything apart from "saving money", which is a bad reason to do anything in the long term.
It's been relatively stable, but only because the federations have come in and propped it up, and because it's been stripped back and stripped back.
The plan released by NZ Football last November was a hodgepodge that valued keeping as many people as possible happy over true alignment. The idea that one team being promoted and one being relegated (after accounting for all the restrictions on which teams can be relegated) every four years opens the door to aspiring clubs was laughable.
Some of the modern context, off the top of my head
A, the existing national league entities are for the most part a financial mess, most could disappear tomorrow with little to no impact and no-one would miss them;
B, many of them struggle for support and a true, top-to-bottom club feel. winter clubs are where full-time employees and player/coach/support/volunteer bases are.
C, also, the bulk of player development work is being done by 'winter clubs' already, so they should be embraced and promoted, the pathways should be clear, and not involve jumps every time winter becomes summer and ice versa;
D, many talented players aren't involved in summer as things stand, often because it's too much football or because it means changing environments;
E, the quality at the top end of the NRFL Premier Division, and to a lesser extent, at the top end of the Central League matches and sometimes beats the national league;
F, Covid-19 is forcing conversations to be had up and down the country about mergers and the like. work hand in hand with this, get people talking, and an aligned system is there to be had.
Of course, there are plenty of specifics to be ironed out, re cost, format etc. but the basic ingredients are there.