Sapping Attention: How badly is Google Books search broken, and why?

Here's an example. While writing something, I became interested in the etymology of the phrase 'set in stone.' Online essays seem to generally give the phrase an absurd antiquity--they talk about Hammurabi and Moses, as if it had been translated from language to language for decades. I thought that it must be more recent--possibly dating from printers working with lithography in the 19th century.