yes no_std for kernel or boot code or MCU boards, that's what rust-embedded is doing and I think it's fine.
many embedded boards typically have 16~64MB Flash running Linux with musl, one rust binary statically linked can easily exceeding 10MB. multi-entry is hard to manage when you have quite a few unrelated tasks, so yes I really need a true shared lib based rust for the mid-range embedded boards, which are, quite a huge number.
I'm not sure what you mean by multi-entry, but it's hard to beat a busybox-style binary for code-size, especially with LTO. If you're building everything into a single filesystem image anyways, this is almost always smaller than dynamic linking.
many embedded boards typically have 16~64MB Flash running Linux with musl, one rust binary statically linked can easily exceeding 10MB. multi-entry is hard to manage when you have quite a few unrelated tasks, so yes I really need a true shared lib based rust for the mid-range embedded boards, which are, quite a huge number.