This response ignores a relatively new source for logs and ore. Voidwatch and events with a similar reward system to Voidwatch, a system which rewards players with innumerable logs and ore per every desired drop, are probably the main source of these materials now. Personally, I have gone from never selling a log to an NPC to selling almost a dozen of them every time I Watch a Void.
Unlike harvesting, it is generally not possible to participate in these activities while naked and be met with success. Many pick-up groups have tried this approach and failed, I'm sure.
This means inventory space is very limited, to perhaps ten spots at the most, and items such as logs and ore which do not stack are either sold to an NPC merchant or thrown away on the spot. These items never enter the player economy at all.
I can not speak for everyone, but if I could stack logs and ore, I would be much more likely to sell them to other players after collecting 12 rather than selling however many I did not throw away to Ghebi Damomohe just to clear my inventory.