You could absolutely do that bread trade (if you could convince a baker to lend you a loaf of bread), but then a smart baker wouldn't drop their prices at the end of day because they know a short seller needs to buy a bread to cover their position. The example is also wrong because stocks don't go off like bread does. For commodities that keep better like frozen orange juice or steel you can definitely borrow (for a price) a few hundred tons of most commodities if you want to short it.

For some reason people think borrowing a stock and selling it is some super nefarious plot to kill companies, but apart from some special circumstances like secondary offerings or employee equity compensation there is really no reason a company should worry overly much about their stock price. If the company keeps making a profit, no amount of short selling can make it go bankrupt.