Why doesn't .bashrc run automatically?
Been there, done that. What I came aware of, OS X doesn't read .bashrc file on bash start. Instead, it reads the following files (in the following order):


/etc/profile
~/.bash_profile
~/.bash_login   
~/.profile


See also Chris Johnsen's informative and useful comment:


  By default, Terminal starts the shell via /usr/bin/login, which makes the shell a login shell. On every platform (not just Mac OS X) bash does not use .bashrc for login shells (only /etc/profile and the first of .bash_profile, .bash_login, .profile that exists and is readable). This is why "put source ~/.bashrc in your .bash_profile" is standard advice


I usually just put the things that I'd normally put in ~/.bashrc to ~/.profile — has worked so far like a charm.