I think the consensus is that W600s, T3s, N173s, T5s, and similar issues are baseball cards and can be considered rookie cards. Their method of distribution or size was not something I thought excluded them from being baseball cards.
Technically, T cards were not directly available to many people (children) because they could not buy tobacco products. It's not a perfect analogy, but as you said in post 75, "the point isn't really if Midwest kids in the 30s could find one, it's can we find one?".
W600s do have a long issue date but there are four different mounts and also team changes that can help date them. For example, Old Cardboard consider the W600 with Bresnahan on the Giants as his rookie cared
https://www.oldcardboard.com/ref/roo...tail.asp?id=27 but not the later one with him on the Cardinals.