Because it doesn't need to be better. It's an embedded application - if the core does the job exactly what it is intended to be, why upgrade? What do you expec

Because it doesn't need to be better. It's an embedded application - if the core does the job exactly what it is intended to be, why upgrade? What do you expect more from an eth chip when it already provide full 1gbps capabilities? In other words, there is no room to be better. It could be more power efficient but it is alway efficient enough. Also changing the core will cost a huge amount of money as it needs to change the production line. Using more recent tech such as ARM isn't always cheaper or better.