The usual argument is that it is a distraction when you’re designing a language, and it leads to programming languages that are all excellent for writing compilers and parsers, but not particularly good for other things.

Since the majority of programs are not compilers, it might make more sense to focus on interesting things that aren’t relevant to compilers.

Some ideas from the top of my head: async I/O, a great SIMD story, effect systems, robustness systems for long-running processes (I’m only aware of Erlang/Elixir), and many others.

Compilers do exercise some things, like error handling and memory management, but they’re not particularly difficult or interesting in general.

The problems with bootstrapping a self hosted compiler are often greatly overstated.

I would go so far as to say Zig even tries too hard to solve it (although they reused existing technology they already wanted, so it was almost free). You can bootstrap a self-hosted compiler to new environments by porting the source, cross-compiling it, and scp'ing or otherwise downloading it over to the target. And that's if you don't want to just use QEMU to develop it. We already do this exact thing when developing for embedded devices or often any type of aarch64 programs.

What additional cost does it have to implement the toolchain in C? I would say there is some benefit in terms of implicit testing to have a compiler self-hosting. But having a toolchain in C also has real benefits.