What do retailers want from organized play? Well, the easy answer is sales, but like most things, Organized Play isn't easy.
As a publisher, the most efficient way to create an organized play system is to put a bunch of stuff in a box, and get that box to the retailer. In general, that's what most publisher-based OP programs are, stuff in boxes. SIB.
What's good about SIB
A consistent OP system provides continuity for players. They know what to expect when they show up for an event, and thus the expectations are easy to meet. (Unrealistic expectations on the part of your customers are a killer!)
They provide an easy solution to the problem of holding events in the store. Everything's provided, including instructions. If there's a problem, the better publishers provide some sort of customer service support.
It's economical. Most SIB's are either free or cost so little that the bump in sales from the event covers the cost. A good deal for everyone.
What's bad about SIB
In markets where there is a high density of game stores, competition can be fierce. SIB events homogenize the store's events. If there's five stores running the exact same events (or worse, the same events on the same nights...say, Friday!) there's little reason to go to any particular store. As such, if there were 30 players in the area, but each simply goes to their closest store, each event only attracts an average of 6 players. Not the critical mass events require to be considered successful.
What's this mean? It means if you're developing an OP program, realize that you've got a different problem to solve depending on the store you're dealing with. Stores with competition are looking for ways to stand out from the others. Stores that are the only game in town are looking for ways to fit in.