I'd say that's more of an annoyance than a feature. The reason vendors use C is because it is there, comes with compilers, ides, tools, operating systems, etc. that will all work out of the box as soon as they get the compiler going on a new hardware platform. Just a critical mass of stuff that they need that conveniently is right there. And when you need to add just a few tiny things, you are going to stick with what's right in front of you instead of rebuilding all of that from scratch.