Why are drivers and firmwares almost always written in C or ASM and not C++?

Question

I am just curious why drivers and firmwares almost always are written in C or Assembly, and not C++?

I have heard that there is a technical reason for this.

Answer 1

Probably because c is still often faster, smaller when compiled, and more consistent in compilation between different OS versions, and with fewer dependencies. Also, as c++ is really built on c, the question is do you need what it provides?

There is probably something to the fact that people that write drivers and firmware are usually used to working at the OS level (or lower) which is in c, and therefore are used to using c for this type of problem.