CKAN, the package manager for Kerbal Space Program mods, works by having a central metadata repo that they accept pull requests against for adding metadata for new mods, and then the mods themselves are hosted on Github or SpaceDock or wherever.

It's not quite as automated as publishing a NPM or Composer package, but it's close and works well.

It's been many years now, but if memory serves...

The precursor system to Curse was actually originally a shared SVN server a group of addon authors (called Wowace; still around somewhat) were using to collaborate on addon development. SVN checkouts were so convenient for distributing addons that the authors started using it to keep their own addons up to date, and then usage started to rapidly spread among "ordinary users".

Unfortunately, the traffic every time a new patch came out absolutely smashed the server and generated enormous bandwidth bills. Various attempts to fund it via donations or sponsorship went nowhere.

Curse had been knocking around in various forms for a while (I think they were a guild at one point, and already had a failed pivot to a "gaming community" behind them), but they rose to prominence by, basically, taking over the SVN server and finding ways to keep the lights on.

Switching to github would be coming full circle in many ways. And it would have some advantages, but I'm not sure how happy github would be to act as a distribution network for addons.

Note that 1.1 million clones and fetches in a week for the CocoaPods repo caused major strain: http://thenextweb.com/dd/2016/03/08/cocoapods-popular-basica...

Using github as the backend for a Curse-clone would probably exceed that handily.

Not that there's anything wrong with the Curse client from a user standpoint, but it might be worth someone's time to write a client that runs off of github. More open and all that.