That's sort of the FCC's fault; it's very hard to get a high-bandwidth device certified under FCC regs (e.g. part 15) if it doesn't have a locked-down processor that controls radio functionality. See this article about the FCC intentionally/unintentionally locking down Wifi routers due to licensing requirements: https://www.wired.com/2016/03/way-go-fcc-now-manufacturers-l...

I'm sure if it were up to apple they'd be putting high-level radio functionality in the main CPU. It's cheaper that way, and matches with Apple's security/privacy-oriented marketing.