The difficult thing is getting it ported correctly. As several people have shown, it's easy to get Go running. However, getting Go running properly in such a way that you can continue to get updates from upstream is much more difficult. So you end up with ancient versions of gmake, gcc, python, mercurial, Go, etc., all mostly-functional but no longer getting bugfixes, because it's much more difficult to make a nice clean port that can be accepted into the upstream.
Oh, and given that the major web browsers all seem to be written in C++, and we don't have a C++ compiler... that's problematic.
