Rust is keeping macOS Arm as Tier 2 as well, mostly not because of lack of interest but because CI platforms can’t support all the demand for Arm builds. MacSta

Rust is keeping macOS Arm as Tier 2 as well, mostly not because of lack of interest but because CI platforms can’t support all the demand for Arm builds. MacStadium, Azure, AWS and others keep adding extra capacity but the build queues are still too long. So you either promote Arm Mac as tier 1, but now every PR takes extra hours to get merged, or you keep it at tier 2 for now and only build on Arm, say, once a day. Rust developers choose the later, because with their commit traffic they can’t afford such delays. As the build machines capacity increases arm macOS will be promoted to Tier 1. Don’t read too much into tiers. Tier 2 is still pretty well supported from a language user perspective. Julia situation is pretty much the same.