ELI5: Why haven’t we fully explored the pyramids yet?

The void isn't like a room we simply haven't entered, it's more like the equivalent to an empty space inside the walls of your home. It's there, but there are no passages leading to it. About 75-80% of the interior volume of the pyramids is solid stone as far as we know so it's much less like a modern building and more of a huge pile of stones that happens to have a few open spaces with passages leading to them.

Here's an article that includes an illustration showing just how solid they are as well as the recently discovered void and more info on how they found it using cosmic rays of all things: https://www.science.org/content/article/cosmic-rays-reveal-unknown-void-great-pyramid-giza

I'm still fascinated by the 20 cm by 20 cm shaft in the Great Pyramid that they sent a robot in to explore: https://www.techexplorist.com/robot-reveals-inside-great-pyramid/30245/

Because why? The pyramids are not a fun park or escape room, they are a piece of art. How would you feel if we'd tear Mona Lisa apart to check if there's some older painting below the outside layer and the canvas?

So I just learned this recently, but apparently after the whole Victorian "smash and grab" thing where Britain stole all the art that was or wasn't nailed down (there's a lot of feet and footless statues lol), archeologists went to sites and realized how much knowledge was destroyed by their predecessors who only cared about impressive finds they could show off

Technology and techniques are always improving, so now when they find an archeological site, they excavate only a fraction, leaving the rest for future generations who will have better tools.

Obviously, non-destructive methods are still on the table, but I found that pretty interesting

Simply, because that would involve disassembling them, potentially causing collapse and destroying more than we would find.

Couldn't they have found something like that ages ago?...

How on earth is this just happening in 2023. Ultrasound, xrays, whatever. SOMETHING would have shown this cavity.