Because there are now relatively simple, portable languages that vastly improve on C's safety and virtually non-existing type system, in order to prevent a lot of easy but critical security issues.
I say that as someone who's been writing C for decades, and still does very regularly.
No, they should have definitely thrown away their entire codebase and embarked on a serious migration project to proven industrial-grade solutions like Zig or Nim.
(sarcasm)
In my experience, it’s the developer that matters. A not-a-very-good-developer can produce buggy code/bad architecture in any of the strongly typed advanced type system languages, too.
So I take it you're still mostly writing your code in machine language (who even needs a macro assembler)? Or BCPL?