Up here in Northland there are many "private" beaches. Much of this area is in private ownership. There is still much that isn't. I'll be the first to say I am very lucky to live where I do, and even luckier to know people who will at the right time give me free access.
What many do not understand or even know is that private land owners do not have to allow you access across their land, but they cannot prevent access to the beach. Its a fairly simple concept, but an easement is often found if you are willing to look for it.
Up here there is more fear than fact. Many people feel they have no right to access, but if asked some will still allow it. The repercussions for anyone on private land "coming to grief" falls on the land owner and is classed as negligence. This is especially the case if the land is part of a working farm (often the case up here).
Reality is I do pay a very small fee to access some locations. Other public locations are harder to access, so less frequented, and I go there too. I also fish populated beaches and easily get a feed if I put in the effort. I am also aware that I live in an area that is known for its superb fishing, but I don't own a boat and know few people who have spaces to take me, so I make my own plans and go exploring.
My opportunities, while it might seem are better, are, in my opinion no better than anyone elses. When I lived in Palmerston North I had restricted access to some very good locations. When I lived in Wellington the boat fishing areas were far more productive, and the local shore fishing limited. I've fished Hawkes Bay, Bay of Plenty, Far North, South Island, North Island's west from New Plymouth south and all around Wellington. The one thing I've learned is every location has restrictions, and every location has opportunities.
The simple act of fishing is a gift, and may well be a right by definition. The factors that make up where, how, when, and who with are all privileges to me.