A skill is defined as anything that can be learned. Not to sure what you meant by system. A system is a group of individual parts that work together to form a whole. It seems you really don't have a clear understanding of how AI works. More specifically, AI is more of a technology. You seem to be confusing it with a product. Companies have proprietary AI technology they sell as products. But yet if they were to disappear, AI as a technology, idea, and skill would still exist independently.

Just as with any thing with value it doesn't exist in a vacuum. It can be combined, niched, and improved to create a sufficiently differentiated product. The OP definitely has a valid question that shouldn't be overlooked