Given the scarcity of used units on eBay, it's reasonable to infer that Uniden has not put enough SDS scanners into the market to ease demand. Which means discounted sales are unlikely if there is still a scarcity situation.
Well yeah true, they are not "mass produced" as we know the term with consumer electronics, such as an Echo Show or a coffee maker from best buy, but they are not scarce, every single reputable scanner outlet has them in stock and ready to ship, you can have one on your doorstep within 3 days any time you chose.
If they calculate that a holiday discount will entice people on the fence to buy one, and in so doing they would make more $$ overall than if they didn't offer a discount, then it stands to reason that they will do it, wouldn't you if you were calling the shots ?
I think the scarcity of used units on ebay can be attributed to the fact that there are relatively few out there, relatively few people that even want a police scanner, and the majority of those that have bought one are quite happy with them and not looking to get rid of them. Once the SDS 300 comes out we are likely to see a flood of them on the used market.