At the beginning of such a case, LE observes the evidence (missing person, out-of-character change in routine, expected mental condition, last known location, surroundings) and decides an action plan based on known issues, executes that plan and prepares next-steps, such as, the more information they gather the more they determine a most-likely scenario and adjust the plan accordingly.
In this case, we've seen LE execute interviews and searches right off the mark. As time progressed LE presented with a presser that left us believing LE believed MT may still be alive, probably because they did not locate a body and the family followed suit with their own media interviews.
Then, we witnessed the "Mollie may be alive" commentary all but disappear for a bit, with that replaced with conjecture by a member of the family that "Mollie was abducted by someone she knows". No body, so she must have been abducted and maybe being kept alive. Is that realistic? Not with a positive outcome.
Beyond simply holding out hope, the family needs some method of attempting to keep this case stirring in news cycles and in public discourse. If LE and the family related they expect MT to be deceased at this point any garnered attention will dissipate faster than vaporous creek mist on a hot summer morning.
What we have. No MT. No body. No witnesses to the event to date AFAWK.
That's where we are.
The odds are against a positive outcome. If FBI begins to pull resources then we may assume it's definitely a waiting game until harvest time, if they're lucky. Many such victims are discovered relatively close to where they were last seen or expected to have been.
Beyond against all odds of finding MT alive, all many can hope for is LE recovers MT sooner rather than later, despite there being hundreds and hundreds of acres of corn fields....