It's that he has to deal with litigation, keeping the site up, doing the podcast bi-weekly, and on top of that deal with all the retards on the site, so he has no free time to actually sit down and work on it.
Also Sneedchat that he wrote in Rust had a pretty bad XCE exploit so making RuForo will be a major task, because not only will you have to write an entire forum suite from scratch, you'll also have to do pentesting on it to make sure there won't be any major exploits while being a persona non grata. So yeah, it's on the backburner at the very end of the room right now.