While it may be possible to develop a good wood foundation system it would not necessarily work well in all conditions. I can see using a stone or masonry capped piling if dealing with soft soils or deep frosts. Where I am in Western Washington we have shallow frost and soils that may or may not drain (glacial tills and outwash). We also have more varities of mushroom than anywhere else in the world and same conditions that make that possible also cause wood rot...lots of it. I would consider stone but we also have seismic issues...so..concrete is my friend.
Having said that, I'm sure that Bob and NH are right that the stone set posts last because air moves around the stones. I suspicion that this works very well for a while but what happens is that a debris cap forms and the rot starts at this "rot gasket" (local term).
The one condition that compels me to think of sinking posts is to develop lateral strength (the ol' vertical cantilever) The last time I had to do this I thought of a possible solution (after the fact) which was to wrap the post in corrugated metal roofing, set this in an oversized hole with gravel in the bottom and pour concrete for bearing to undisturbed soil. If the metal was extended above grade it might at least stave off the debris cap effect.