The argument isn't about one or the other failing. For the same reason Cobol and Fortran are still used and iterated upon to this day, GCC will also never "die". It is deeply ingrained into many toolchains used by many companies. The article if vapor because the moment a company wants some C++11 feature in GCC, they have a value proposition - refactor their code base to work on Clang (which may not have feature parity with all their optimization / compiler flags from GCC) or contribute the missing parts into GCC.
And a lot of companies will still go with the latter. GCC is fine, and won't "die". The systemic problem in LLVM/Clang vs GCC is that the former is modular and has an intermediary language that makes new compiled languages much easier to implement a compiler for. The resut is that if you were to write a new compiler, LLVM is so far and away the best choice it isn't even a content. So it has momentum GCC doesn't, and that momentum means it will see much more active development.
And a lot of companies will still go with the latter. GCC is fine, and won't "die". The systemic problem in LLVM/Clang vs GCC is that the former is modular and has an intermediary language that makes new compiled languages much easier to implement a compiler for. The resut is that if you were to write a new compiler, LLVM is so far and away the best choice it isn't even a content. So it has momentum GCC doesn't, and that momentum means it will see much more active development.