I opened a store again and magically got some a couple of days later. Coincidence? I doubt it.
I was coming off of a couple of months of high sales and a lot of listings. I read an article where it had happened to other people and they said that after they came off of high sale months and had a lot of listings that went into unsold as well, they stopped getting promotions for a while. They thought that eBay basically knows that you're not going to let all of the listings in unsold just expire and that you'll either pay or open a store to save them if you don't get a promotion. Who knows if that's the case or not, but it does make sense.