Always remember, because a store is in the top 10, does not mean that they are there for the items they sell, sometimes they are only there because they have a number of accounts that sit the lot. Please NO offense to them,(its perfectly legal with paying accounts, or the CC lots which don't usually stock tso items) intended.
I have a small store, located somewhere in the middle of the list. I try and always have things like tip jars, food processors, telephones and smaller items that are needed in every house. Yeah, I wont get rich, but i am determined to be on that lot and provide whatever the customer needs.
Another problem is that when a new store owner sells old stock from the merge, their prices are much lower on everything, especially things like toilets, showers, stoves and fridges. Once those are gone, we must buy from the new catalog, and those items are MUCH pricier than the merged items.
Many sims think our pricing is too high and we are trying to make a HUGE profit off of them, Not The Case!! We can't sell them items at the old rate. SOOO, store owners stop stocking those items. We have to invest a lot of money to buy for you.
I agree with the previous poster, look at the bottom of the list...or maybe yet come visit the stores that sit in the middle, we are in no mans land LOL
Visit lots of stores, no matter where they are on the list (hate the list) you will find what you need.