Compilation can be very intensive, and it's detrimental to a developer's workflow if they must wait for long recompiles.
Rust was originally written in OCaml before being self-hosted, and it wouldn't be as fast (or would be even slower ;) ) today if it was still OCaml.
And remember, low-level =/= poor abstractions. I think there are several novel abstractions available in Zig which the compiler devs probably want to make use of themselves.
They might have good language abstractions, but manual memory management is simply an orthogonal implementation detail to solving a problem — dealing with that is simply more work and more leaky abstractions.
Rust was originally written in OCaml before being self-hosted, and it wouldn't be as fast (or would be even slower ;) ) today if it was still OCaml.
And remember, low-level =/= poor abstractions. I think there are several novel abstractions available in Zig which the compiler devs probably want to make use of themselves.