The main reason C++ is still in use is not the zillions lines of existing code. It's the lack of alternative. Other languages may excel in one or two areas, but

The main reason C++ is still in use is not the zillions lines of existing code. It's the lack of alternative. Other languages may excel in one or two areas, but if you consider the whole ecosystem, C++ is still the best. The availability of highest quality compilers for all possible architectures, build tools, IDEs, static analysis tools, profilers, libraries - all of these factors combined make C++ the first choice for many applications. C++11/14 didn't just "happen." A lot of smart and highly paid people invested their time and expertise to make it happen. Were there a better alternative to C++, they would invest in that alternative rather than putting their time and effort into C++. It's also great to see new ideas being borrowed from other languages and applied to C++. It shows that C++ is not a niche language some people like to view it.