That is a not-unreasonable take, Jar Jar, but the idea won’t let go of my brain that easily.

You see, the reason why most old castles and ruins on Earth are little more than foundations are because they’ve been robbed out by later inhabitants. If the buildings were merely abandoned they could last for hundreds or thousands of years, as seen with Mayan and Aztec temples. I would imagine that the huts probably would have collapsed over time, but the stones would still be there covered in a growing layer of rain-deposited sediment. If Luke was on the island for a few years it’s easily possible for him to have rebuilt the ones we see in TFA which consist of about two huts and a wall.

All this to say that there’s the potential for an unknown history regarding the island and its unusually pristine structures. Perhaps it was Luke, perhaps it was magic, perhaps it was a race of monastic House Elves which lived on another island and risked attack from violent tribes to keep the relics of a long-forgotten people in working order.

I only wish that the imagination of the viewer would have been given reign over these minor mysteries and reserved explanations for things with true import in the story.