The stores change prices all the time on all kinds of items. Have you heard of sales, clearances, price increases, or simply the same items offered at very different prices from different stores, no? Pretend Apple in this case just ran a large sale event selling $599 iPhone for $299 - are there indignant people suing stores every time the store runs a sale, is there a surge of lawsuits every Black Friday perhaps?
I think you're kidding yourself, akin to people who think the government sets prices of all items in all stores - it makes it easier for their brain to understand the law perhaps (and those people ignore the fact that the same item is available at very different prices at different stores). You claim that the iPhone market is regulated - can you show me where in the US the regulation it says that manufacturers of goods, and/or stores, cannot change prices of devices like iPhones at will?
As for people wanting to pay less, of course that is true of all markets, including the stock market, and yet the stock market doesn't collapse just because each sale is an open market transaction - even though you'd call it "crazy" and "precluding inbuild assumption that people do not want to pay more". I've lived in a communist country before where the government in fact set prices for everything. Everything was very affordable, on paper. The reality was that shelves were literally empty, and in order to buy anything you had to pay bribed, or barter, or swap favors, whatever you want to call it, the prices were essentially market prices after you add the cost of obtaining the item at the low price set by the government. You simply cannot go around the laws of supply and demand.