So what is the appeal of an obsession? The kind I'm talking about doesn't matter, and that is absolutely key. Sports are an example. Most Americans are viewers, not participants. In the end, which team wins does not change their lives in material ways, though they may care passionately about their team.
The friendly online dictionary defines hobby as: "an activity or interest pursued for pleasure or relaxation and not as a main occupation." I think this is what I'm talking about, though the online dictionary defines obsession as: "the domination of one's thoughts or feelings by a persistent idea, image, desire, etc." This sounds less pleasant than a hobby.
Maybe what I'm talking about is something between a hobby and an obsession, which is the way many Americans treat sports.
Crucial is the idea of an amateur, I think: a person who does something out of love, for pleasure, not to gain money or fame or to change the world. A peace activist is not an amateur, because she believes that what she does matters, that the world must be change.
A professional writer is no longer writing out of pure love, because career considerations have become important. In a sense, writers destroy their own pleasure when they go from amateurs to pros. That doesn't mean that writing can't be fun, but there are other issues now.
Having an obsession can allow us to rediscover the old fannish pleasure, and I suspect it can be a way to recharge. Wow! I remember now! Fiction can engage our emotions, not our sense of craft. We don't have to always think about the market. Fiction can be fun.