Considering they document their build process very carefully, I can only imagine they wound up standardizing on that library a long time ago and keep using it to this day.
Yes, even if there is any recent open source alternative to build 16-bit code, selecting the 20 years old compiler binaries (http://en.wikipedia.org/wiki/Visual_C++) for which it can be easiest to be sure they haven't changed (there's still enough CD's around produced at that time, I believe I still have one too) is a damn good decision.
Hmm... 20 year older binaries? Anyone ever read "Reflections on Trusting Trust"? Perhaps they don't trust newer code from MS? Think about it, MS can't backdoor an old binary.
