I don't believe I have ever seen anyone say "Dirt is not conductive" and not be corrected.I maintain this for a long time but the majority here is mislead by the general 'understanding' of grounding as it is propagated by the MHE.
When it comes to safety, I believe it's a good idea for people to crawl before they walk. That is, if we get it into someone's head the simple message, that the earth is a lousy conductive path for our purposes (i.e. for people that work with up to 480V) then after that has been established then there's no harm in exploring the specifics.
If someone were to come away from this discussion thinking they could omit the EGC of a circuit and drive a ground rod, that would be no good.