Is there something like an Extract-SPICE tool that takes a circuit and gives you back a text rendering of it ?

Practically No, the stack-up of metal layers often hides the gate structures underneath, and the billions of process cells may not all be the same.

Theoretically Yes, as an ion-beam-mill and electron-microscope combination machine can slice up semiconductors layer-by-layer. Given these machines can often also give precise x-ray analysis material data, the exact makeup of the chip can be extracted by competitors given enough time. =3

Now you're making me imagine some kind of 3D-scanning, confocal x-ray fluorescent spectroscope.

Or maybe some kind of hybrid of x-ray microtomography and spectroscopic analysis all in one.

But, maybe the energies involved would be about the same destructive power as some microtome slicing technique...

We already know that X-rays don't destroy chips.