I think part of the reason it isn't getting as much attention is that there isn't all that much mystery. I mean, with Natalee, Laci, and Chandra, something obviously happened to them that was NOT an accident. And here, while you obviously have a family and a group of people who think that there was some foul play and that he is living incognito on some island somewhere, I think LE and the vast majority of people would say it was an accident and they are both dead. It's sad, but it isn't any great unsolved question of life.
There are things that happen like this every day. The few people I have known in life who have died tragically in an accident have all left some unanswered questions. In each case, there are a few family members who can't let go of the idea that it wasn't a random accident, although it clearly was. I think that some people, in a complicated grief, need someone to blame, and can never accept that accidents happen in life and feel some need to hang onto this mission of finding "the real killer" because letting it rest feels like letting go of the person that they love.