I would question the truefulness of this, and also question its legality.
What Walthers might be doing is not accepting small dealer accounts that lack a brick and mortar store to prevent “basement operators” who actually order very little product, only sell at train shows and online part time and who are more a front for a few guys to get all their stuff at dealer cost.
Even then, if I have a bussiness licence, a retail sales tax license, conduct business full time on any business platform and meet their minimum order and credit requirements they might be asking for trouble by not selling to me.
But, back to the main question. In my view, the only hope for model train shops, of any size, is a more stable supply of product, and more uniform stable pricing.
Distributors are dead, and any actions Walthers is taking are more likely a move away from being a distributor to only selling their own products strictly as a importer/manufacturer.
Direct distribution, like Athearn/Horizon is the real future.
Direct distribution with similar price structures to retailers of all sizes would serve the customers better and give smaller retailers, online or bric