points shop sticker for steam

Why are the sims 4 Steam stickers not added to the steam points shop? I know they were obtainable for a limited promotion, but as far as i know people could only obtain one? they should be added to the points shop to be purchasable for the stickers people missed out on. Apex legends has stickers so why not add these ones, i don't understand why they aren't purchasable when its free advertising andI would really like some.