Gnus only got moved into Emacs core a couple of years ago. Lars got tired of supporting fourteen different Emacs versions, including XEmacs, and finally just ti

Gnus only got moved into Emacs core a couple of years ago. Lars got tired of supporting fourteen different Emacs versions, including XEmacs, and finally just tied it to core. The ELPA package repository is developing the concept of core-but-installable, whereby a package is shipped with core, but a newer version can be installed via ELPA, and that might be a viable path for Gnus. I don't think the issue was needing Gnus in core, so much as it was avoiding all the multi-version support headache. But one could simply declare that the package is only supported for the two most recent Emacs versions, for instance, and call it good.