Sorry for coming in late on this thread....

"I don't see how fresh rock breakage vs pre-existing faults matters in this stress vs strength discussion."

Did anyone consider the idea that the crust is not one solid unfractured block? If it were, there'd be no rocks, boulders, mountains, etc...

The crust is fractured and cracked all over. I doubt there are any large contiguous blocks of crust larger than several hundred cubic meters.

Active faults simply occur where such weaker fractures have accumulated after being forced to move due to outside forces, ie tectonic motion.

Brian