Honestly, to answer the main question of the thread, I have two reasons as to why I haven't been forum RP'ing.

First and foremost, I left TFF for quite a while. With that, I hadn't joined a new forum community (seriously, that is. I've posted in one or two and left them soon after) so forum RP got thrown out the window. As it stands, I guess I got turned away by how inconsistent things can be with responses. If you've got one person who needs to respond to continue the story-and they don't? You're screwed. Sadface.

Second, is because I've been enjoying active RP in a game environment (namely FFXIV). It sort of relieves the issue of waiting for a response, as the most you'll be sitting around is half an hour or so. If someone falls inactive, there's usually an excuse you can use to explain it and in the case of relationship RP, move on. There are some downsides to it, admittedly, but overall I find it a good experience.