It's all in the automotive dept. person's ordering. They often do not reorder stuff because they are lazy and do not like to stock shelves.
My wife has worked for Wal-mart for 15 years. She is in the cash office. We got on her manager awhile back because their automotive dept. person was not ordering quite a few items. I use the Mr. Clean car wash system (No Spots!!! ) and they didn't have the filter inserts for like a month. After talking to the manager, they had then a couple of days later and the employee got reprimanded for have way too many empty spots on the shelves.
If it is synthetic oil, no Dino oil is used and the hurricanes would not effect production as far as I can tell.

 

Wow. I get fleet pricing through my work, cause they are nice enough to give it to me, which happens to be the same price that any dealer, or store would purchase it for, such as walmart. And the oil that I purchased still cost me about $8 a quart. However in hindsight, I dont have to change my oil for 30,000 miles so.......