eBay definitely want to encourage fixed price listings for anyone that lists fairly regularly - auctions still make up a fair percentage of sales, but when you read the way the statistics are conveyed, it becomes clear eBay prefer to encourage fixed price listings. Just over half of all sales on-site are BINs, around 52% I believe, which isn't the biggest difference in the world, but it's always presented in a way that would suggest BIN listings are more popular and successful, and with noticably less interest in auctions for a lot of sellers - i.e. less bidding activity, items selling at lower end prices - it could be argued they're encouraging a more successful selling strategy for sellers because higher sales / sale prices benefit eBay just as much as they might a seller.
I'm not saying it's the way to go for all sellers, but eBay would work on averages and site-wide statistics rather than on an individual basis.
Auctions in collectible categories (which includes some new categories like craft items), are included in the free listings for store packages, and are charged at a reduced rate when not free ($1.00 instead of $1.50), so for some sellers who prefer auctions, a store would still be of more benefit.
You could also use a couple of different non-store IDs to access more free listings per month.
