That is an oversimplification. Apple has more money than it could possibly hope to reinvest in its core business. When that is the case, and when the stock is undervalued as is the case with Apple, stock buybacks are a great use of a company's cash.
The point behind stock buyback is simply to assert some confidence in the stock. Which means the market does not have confidence in it in the first place and probably has negative momentum. Most cases I have seen the market is correct. So even if the stock is bought back the increase in the price will be temporary as the negative momentum will surely vaporize the stock increase. It does not help anybody but investors trying to make a profit in the short term. I have not seen a single stock buyback work. I would rather they throw money at anything but this.
That is an oversimplification. Apple has more money than it could possibly hope to reinvest in its core business. When that is the case, and when the stock is undervalued as is the case with Apple, stock buybacks are a great use of a company's cash.