GCC stagnated until it received competition froom LLVM (clang). something similar seems to have happened to C++ the language itself, and i think viability of competing languages has played a large role.
C++11 and C++14 have done a lot to enable users to write clean, efficient code. I probably would not be using C++ today if I were forced to write in C++03 style. I am still not convinced that C++ has gotten any easier to learn over time. But for those who know how to use it well, no language ranks better in allowing users to write clean, efficient, and portable code.