k) Add a proper exponent operator
Won't and Can't do this efficiently. Not all CPUs have an intrinsic way to do exponention. This is specifically why it's a library function so it is obvious that it is potentially a non-trivial operation. Once again, not everyone uses an Intel CPU.
q) Add a proper rotate-left and rotate-right bit shifts
See the answer to exponent operations. Simply put, not all CPUs have this. I would however welcome a standard library function for this like pow for exponents. Which the compiler could inline to a single instruction if the CPU supports it.
I agree with most of your points, but I can't really agree with your logic on these. Hardware floating point support wasn't common until the 486 days. A lot of lower end CPUs used to omit support for division. That didn't stop C/C++ from including support for those features.
I think the reason for omission is simply that the operators are nothing more than syntactic sugar. Anyone that needs those operations can write them quickly without putting much thought into it. They were probably left out originally to keep things simple in the early days of C. Now the standard committee seems very hesitant to make changes to the syntax of language, so they probably just look at these things as nice to have but not worth changing syntax over.