The embedded and systems space are hard and require special talent and knowledge. You can't just take some front-end React developer and get them writing quality systems C code in a weekend... people spend entire careers in that space, and the number of people interested in that work shrinks by the year (look at all developer surveys).
That's the extreme opposite of raw C (or raw JavaScript, etc.) in which it's very easy to believe that you have solved an issue, only to realize much later that you've been entirely misunderstanding some constructions of the language and (if your code somehow managed to land) you have made the entire product unstable or insecure without realizing it.
Of course, there are tradeoffs to each approach. But I believe that investing in Rust was a great initiative from Mozilla.
I think the language difference is a red herring.
I always felt they were hostile to understanding OSes and problems/solutions they provide and thereby limiting themselves to mostly junior C devs who didn't rock the boat by making real OS features for the JVM.
Most developers you see/hear/interact with are not C developers - rather they use higher level languages mostly to build web apps and mobile apps.
I don't think C is special in this regard.