Are you guys seriously getting your heads around a decentralised forum? Forums are things of the past and those that survive are because they were launched and were successful in the past. I think the only thing that hasn't completely killed them is that a lot of people forum during quiet times at work.
Also the reason BTT survived?
I think BTT is just special and maybe some things like signature campaign has been a key to keeping here going.
The reason forums got outdated could be because of lack of the modern day UI/UX amongst other things.