A Curse in Disguise?

I'd say HIV is very successful. The virus's selfish interest lies in keeping the host alive long enough to spread the virus to others. It does that, and even better, the host may remain unaware of the virus for some time while spreading it; that stealth is important because once the host becomes aware of hosting the virus, the host may behave in ways that don't spread the virus as much. When the host's behavior changes so, it makes that host less valuable to the virus — so it then doesn't matter so much (to the virus) whether the host dies.

Yes, but it can only be spread to one or two other people, and very slowly. If someone were born with HIV, it won't be passed on to anybody else for at least 16 years (assuming they do it all legally), and perhaps a lot more. Once the host does start having unprotected sex, it is likely that they will be in a long-term committed relationship (and trying for a baby), so the only person they can pass it on to would be their partner, and they hopefully aren't sleeping around. In a person's lifetime, they probably won't spread it to more than ten people, even assuming they were born with it. Add to that the chance that the host could quite easily find out about it from a doctor or die from it, and the virus doesn't really stand very good odds.