A large number of customers are quite new to dolls, and the first one you get is generally the one you make your biggest mistakes with. If you make a mistake with a standard softness doll it is almost never as bad as with a super soft. As a vendor, it is a bad look to have your product get tears very quickly and get ruined in a year or two. It also doesn’t ship as well. If a customer is an experienced doll owner/buyer, not listing it is not an issue as they’re aware of it already and they request it.
If a new person requests it, the vendor will discuss the fragility and longevity of the softer TPE, and let them know a few extra tips for caring for it, and then re-check whether they wish to go ahead.
The vendor doesn’t do that to absolve themselves of all responsibility, but to properly inform the customer and ensure they have realistic expectations. Also keep in mind that the standard TPE WM had years ago is different from the standard formulation now. They improve the formulation’s softness and durability over time.