A vertically integrated company owns increasing amounts of production of their end product. Apple is vertically integrated, they have products where they make the CPU, the device, the OS, and retail the devices. But ultimately they only sell the end products.
If Apple were to start selling CPUs, you could argue that they had a similar model, but they don't (and won't because their CPUs are a competitive advantage).
What Amazon and SpaceX are doing isn't vertical integration in the classic sense. While Amazon sells AWS, they also have an online retail platform. Their retail platform consumes AWS services. Similarly, SpaceX is both the supplier of launch services and the consumer of launch services.
Amazon's retail operations are profitable, but by being their own best customer, they help Amazon drive profitability and demand for AWS.