I replayed Ocarina about a year ago, and one thing that really struck me was how many of the mechanics were really fun, and were preserved in the later titles. No matter what iteration of Zelda you run (except maybe Breath of the Wild), a huge fraction of the gameplay was using the same stuff that was on the N64, in 1998. That was still early in the 3D transition, and a lot of interface conventions hadn't been worked out yet. Between Mario and Zelda on the 64, Shigeru Miyamoto ended up defining many of the standards for how to interface dual thumbsticks into a 3D game. (and ended up cementing the very idea of dual analog thumbsticks into the controller definition, although I'm sure the hardware guys at Nintendo had a lot to do with that, too.)
Ocarina is one of the games that's genuinely interesting to look at, from a historical perspective. So very many historical games aren't that much fun anymore, especially in the early 3D space, because the interfaces varied so wildly. They are often very uncomfortable for a modern gamer and not much fun to actually play. Ocarina is still fun, and the rough spots there show you some of the harder problems in a 3D game. Camera control comes to mind, which didn't work that well in either Mario 64 or Ocarina. Well, the control itself was fine, but the logic the camera used when chasing was quite bad, which was a very common problem in games of that era. Somehow, they've worked it out since, so that cameras nowadays are usually quite comfortable, and Ocarina gives you a hint as to how hard a problem that probably was.
At the time, I thought of the 3D transition as a huge net loss for most game types, as game quality took a huge dive in that time frame. My belief at the time was that gaming was set back about ten years, that the whole period of about 1996-2006 was sharply inferior to the 2D games in the early 90s. 3D was so hard, and took so much mental effort and so many more assets to be built, that there wasn't much bandwidth left for making genuinely good games. An awful, awful lot were released, but not that many are both memorable and playable today. A much larger fraction of the 2D games, especially from the early 90s, are still fun.
Ocarina and Super Mario 64 were works of genius, and I hope people later will remember just how good they were and just how much design talent Miyamoto threw at those games.
I don't know how long people will still find them fun, but I'm suspicious that the Zelda games as a whole will be rather evergreen, that people will still play and enjoy them fifty years from now. I suspect Wind Waker may end up being the one that's most often played, because its cel-shaded graphics scale flawlessly to any resolution. But all the games are good, and I hope people still enjoy them, decades from now.