Most of the cost of the chip is in the R&D just like in software so the cheap chips cost about the same as the expensive ones on manufacture. For years, people

Most of the cost of the chip is in the R&D just like in software so the cheap chips cost about the same as the expensive ones on manufacture. For years, people have been overclocking cheap chips to make them run like the top end ones which shows there is little difference between them. Therefore price differentiation comes into to play so they can maximise their profit. It's similar to what Microsoft do with the different editions of Windows.