Why are there only two CPU companies in the world?

The production of CPU belongs to high-tech technology. Due to technical barriers and patent technology restrictions, there are only two desktop computer manufacturers in the world, inter and AMD. There used to be a crixs, which was sold to Taiwan Province Province, but it was discontinued. Because of the complexity of its production process and the limitation of patented technology, it has been monopolized by these two companies. Of course, there are some dedicated CPUs produced by other manufacturers, but they are not the mainstream.