This is not C anymore. When you write modern C++, it's much much more hard to introduce memory safety errors. And the logic hides in corner cases, so when you need to review logic, you're necessarily also reviewing memory correctness. I also don't agree with you on the part that logic is much easier than memory corruption - perhaps you haven't worked on systems complex enough? The 70% quote includes programs written in C, which I would argue, has a much higher of memory corruption errors.