DuckThor Evil
Legend
He's one breakdown of costs: http://latimesblogs.latimes.com/entertainmentnewsbuzz/2010/02/anatomy-of-a-60-dollar-video-game.html
That puts the publisher cut at $27 instead of $20 but doesn't include things like advertising incentives, etc which places like walmart pretty much require which will eat another $5 or so, so you are looking at ~$22 to the publisher. And large retailers like walmart etc will also push down their costs to acquire as much as possible simply because they can, so it wouldn't be unusual for then to get the game for ~$30 or so once they roll everything in.
$27 and made by a guy whose sole purpose was to show his business model in the best possible light. I'll take that as a worst case scenario. $7 for returns is highly suspect. Over here stores don't get to just return stuff. They take the hit as far as I know. $15 store margin on top of the $45 is already 33.3%, so quite a bit higher than the 25% margin you are saying. He does seem to have a realistic view on distribution and cost of goods though.