I feel like if you start going down that road, towards “commonly portable”, you naturally end up with one of the not-c variants (zig, nim, etc). ...and ifc, if you start writing a new language, you might as well toss in features from the last thirty years of language design.
C is C largely because its so stupidly (and impressively) portable; if you aren’t drawing that benefit, its likely a case of the wrong tool for the job.
I'm working in medium sized embedded systems (not embedded Linux, but also not the smallest embedded systems). I've only rarerly worked on 8 or even 16bit Microcontrollers. Most of what I work on is 8bit chars, 32bit, Little Endian normal Microcontrollers.
I really don't need the portability, the targets are all the same, however they only have C/C++ compilers. And we can't use GC. Rust would be a very nice choice at least for the application code. I'm not sure how to write low level drivers in Rust, but with FFI I would just push that to the boundaries, and make at least 90% of the applications Rust. But there's no LLVM backend for most embedded processors I work with, and even if there is, the maturity might not be there, and no company would switch to that considering that the next target might not have a backend.
We have to use C, because it's the only thing that we are offered. But for desktop applications I see no real reason to start something in C nowadays.
https://www.mikroe.com/compilers
But as you say, the company needs to give the option to developers.