Craig specifically said that this wasn't going to happen, in one of the podcasts he said people came up to him internally and said "Wait. There's still Terminal, right?" and he said "Yeah, it's a Mac.". The Platforms State of the Union host also said that they had made contact with a bunch of open-source projects with assistance (and in some cases, iirc the OpenJDK and CPython, pull requests) on moving to ARM.