At one point, the pier (structure) was owned by an individual, and the land by NPS. And the owner was going to repair/rebuild, but I think money was a problem. Anyway, nothing ever got started, except maybe some supplies being delivered that were never used (something about faulty material). I think, for all intents and purposes, owner abandoned the pier and the idea. And never got around to demolishing it either, again, perhaps a financial issue. So it sits, maybe till it finally gets taken by the sea. Working to coordinate the various agencies may have been problematic, as well. I think NPS got pier ownership since then, but it has still not been demolished, and that's probably a funding thing, too.
That's my recollection, and I'm sure it's a bit fuzzy, and less detailed than a proper explanation, but it's close.
Frankly, I'm amazed at how long it's managed to stand, even on its last legs, as it has.
User hatterasnc probably knows much more about this and may be able to provide a better, more precise explanation. Or perhaps another local, Alexy?