Well Clang/LLVM is also becoming larger with each release. As for GCC becoming more 'unmaintainable', can you point me to anything supporting that notion? It's certainly not unmaintainable now as proven by them regularly releasing new improved versions which serve as the de facto compiler toolchain for open source systems.
Also when speaking of GCC and how old and full of cruft it is, you need to realize that it's code base is being continously improved with each new release with a strong focus on modularity. It's not the same codebase as it was back in 1987.
I'm very happy Clang/LLVM exists and progressing at a great pace as I see increased availability of open source compiler toolchains as something awesome. Also LLVM really does have some great features like the best-in-class error reporting and it also serves an undeniable purpose as a jit framework for numerous projects.
That said I don't understand those trying to push the idea of GCC being obsolete (unless they are nurturing some political/licence based crusade) as it's a very mature compiler toolchain targeting a large number of architectures and (atleast for me) quite importantly generating faster code than Clang/LLVM.
Also the notion that companies would be afraid of GCC strikes me as odd given that we have Red Hat, IBM, Google, CodeSourcery, Suse etc employing full-time GCC developers.
I hope to see these compiler toolchains continously going neck to neck in the future and thus provide the open source ecosystem with two first class options each with their respective strenghts.