If releases of different products are spread out, then Apple prevents any sort of competition between its own products. While this may seem unrealistic, it does exist.
Your point about the five-month delay is a good one. However, the July 14th release is apparently just an initial update. According to this article, we won't see the low-power Montevina version until the fall. If this is true, then Apple may wait for later versions to put in the laptops.
Maybe for the MacBooks, but all the MacBook Pro competitors are being updated to Montevina in the next month or two, many of them being announced on July 14th itself.
Apple is on the forefront in all aspects other than GPU with it's notebooks, it'd be highly unusual to let the competition gain a 3 or 4 month advantage in processor for the first time ever.