True, but there are also religious reasons against anything else that isn't Assembly or C89, when reading about experience reports about trying to move devs forward to C++ or even more up to date C versions.
It’s very hard to throw away decades of knowledge, libraries, and tooling.
Especially when they get the job done quite nicely.
And a lot of the time you don't have a choice. For example the Xtensa core in ESP32s doesn't have an upstream quality GCC or LLVM backend last time I checked.
GCC toolchain for Xtensa has been available since day one. ESP8266 is upstream, pretty sure ESP32 is also.