I think the majority of folks who think the ginseng population is vanishing are folks who probably have no idea what ginseng actually looks like, have never spent a few hours hunting it with someone who does know, or as you said those who have something to gain from the propaganda (selling seeds, roots, etc).
I read on a website a year or so ago someone who mentioned digging some yellow root (goldenseal) and soon after that post hundreds of people started bashing him for harvesting wild roots because well goldenseal is near extinct (they said). I bet you the large majority of those bashers have never walked a hollow looking for it.
I can show you acres of it and basically no one digs it around here because the price is low and it's way to much like work digging it (unlike ginseng which has much more of a fun factor to it).
Like they say about Guns - - - When they outlaw Guns only outlaws will have Guns !
When they outlaw Ginseng I guess most of us will be Ginseng Outlaws
TNhunter