In a perfect world, one would like to think that LE would only ask for the help they need.
That's why when the media starts to report on a MP story, there is a flow of information that comes out and then at some point it just stops. Lately the information flow in cases coincides with calling off public searches. You also have to consider that any release of information is strategic, usually only giving basic details, and that strategy may very well be to protect the integrity of the LE agency,or "the investigation", much more so than any single case. In the LS case, most of what we are discussing is hearsay and arguable rumors. Imagine the reaction if we knew LE was not following up on credible leads, or overlooking an eye witness account because they didn't like that person or thought an aspect of their account was not accurate. If they do not discuss it publicly, it's like it never happened and there is no consequence.
Not that I always agree with this philosophy, but it has become the norm in these cases.