Stock Market Capitalism is just imaginary numbers made up by rich people to convince other rich people to give them money. It's completely ephemeral.
The fact that it can rise or fall with nothing more than a silly antic from one person is proof about how insubstantial and frankly ridiculous the whole scheme is.
Stock price is really just a present value of future expected earnings. Buying Coke for $100 is because you think the earnings of that share in the future is worth $100. So yes, if the company makes an announcement that it isn't as profitable, the price will go down, because buyers won't want to pay the same for an asset that is returns less than it was expedited to.
Yes, there are complications. Shorts, futures, non dividend yielding shares, and more make it more muddied. At the end of it though, the future expected earnings are what is being bought and sold.