The stock market operates on emotion and bullshit. Most if not all of the market is overvalued compared to historic standards. The more money that enters the market than is leaving, stocks go up. When people take more money out than is flowing, the values go down. There was never a reason for Apple to have a stock price that high, it's merely working it's way back down toward it's true value.
The iPhone is not overpriced compared to it's competition. The nice thing about apple is that they don't make junk, and that sometimes is confused with being overpriced, when compared to junk. The aluminum glass and cloud infrastructure that makes it all work cost more than what you get from the competition. A piece of plastic filled with admittedly great hardware, in some cases, but it's a device that stands on it's own. My iPhone, iPad, and Mac all work together seamlessly, and that's something that doesn't show up on the spec sheet, and no one else has managed to bring to market.