Prices must come down as component prices come down. There is a delay, and it depends on two things.
One, when the less expensive lead (in this case) gets into the manufacturing process. Once one manufacturer starts dropping prices they all will.
Two, is cash flow. Even if the manufactures are sitting on a gazillion tons they will be forced to take a reduced margin if sales get below a certain point - ie cash flow starts to hurt. And in this economy, that could be sooner rather than later. They need to keep their plants running at some minimal capacity.
Reloading is a minor factor and only impacts sales of "target shells"; although some may regret their decision to sell their reloaders a few years back and "shoot cheap factory shells". Alf - I just loaded up another 1500 rounds on the Spolar you sold me. I still need to watch my costs (and I am dumb enough to enjoy reloading) so making my shells is good for my wallet, and keeps me out of the bars where younger women remain a temptation.
My shooting friends have recently had conversations about the hardness of materials used in non Remington STS or Winchester AA shells ( read as ALL others ) primers causing problems with breech faces on over/under shotguns. Problems exhibited are cratered breech faces around the firing pin creating need to have repairwork performed. The problems are believed to be caused by the steel content of the Nobel, Cordite and other primers.
You are right it has nothing to do with the manufacturing cost of the shells on the shelf. But if that store wants to sell some of that stuff on the shelf they better put a price on it that people can accept.