They don't "not get anything", by the way. Lots of subsidies from mainland France, lots of effort to recognise local customs, local assembly and moving to more autonomy from mainland France while keeping all the benefits of being in France.
Interestingly New Caledonia has been French for longer than Hawaii has been American. The difference is that European migration to Hawaii has been much, much higher.
Anyways I don't mean to say it should be invalid, just that as a independentist person living there it must be really angering. If it was 70/30 it would be much easier to accept. France increasing their autonomy and recognition is a smart and sensible move given the situation.
Subsidies and the move to more local governance probably mostly benefit the area around the capital Nouméa, which is of course on the side that voted to remain.
I wonder how palatable a compromise would be where only part of the island becomes independent.
Everyone on the islands benefit from the full French benefit and welfare system and on top of that there are plenty of subsidies, which are in part targeted at the indigenous population, which is actually benefits a lot from the mining industry (a lot in the North where there are the majority).