Last I heard, the AMF and similar organizations were aiming to eliminate malaria in Africa within this decade. That sounds a little ambitious to me, but even if that goal's not met it's certainly not the open-ended problem you're painting it as.

If that's true, I think they absolutely should advertise that fact strongly, as that seems to me to be one of the most persuasive reasons to donate. "You can save a child's life!" and "We are aiming to fix this problem forever and you can help" are very different.