> Also, Microsoft has some magics for executing x86_64 binaries on aarch64 with good performance, so Apple may have a similar technology.

I'm reminded of the patent-sharing agreement between the two. Or, given MS' diversification, they may be willing to directly license the tech. Making the x64 -> aarch64 translation as robust as possible has benefits for both companies, and they're not nearly the bitter enemies they used to be.