How many chip and SoC vendors provide a Rust toolchain? In the case of C, the answer is basically "about as many as provide a toolchain".

In 2016, yes.

All the way through the 80's up to the early 90's, C toolchains only mattered to those that were working on UNIX workstations and servers. On home computers it was just, yet another language, with compilers generating slower code than junior Assembly programmers.

So of course Rust has to catch up a few decades of market use.

sure, use c if that's all you can use, but if rust does target your system it adds no more overhead than c does.

tangentially, ats has had some success in that area since it compiles via c. but I agree that c is less work to get set up with.