Can I try to answer, Lace ? SY's objective has always been Madeleine. They found she could be alive, they never indicated a percentage. It wouldn't have been politically correct. The only chance she could be alive is if she was abducted. So logically they're investigating that line.
That's not logic, Anne, that's emotion.
SY's official line that 'Madeleine could still be alive' is one thing, but the fact remains that as Madeleine's parents, the McCann's need to know what happened, no matter what. In driving the investigations, they know that they are taking the risk of finding out things that could be extremely hard to bear, including the possibility that their daughter is dead, but they take this risk because in 'not knowing' there is even greater pain. The need to know what has become of our loved ones is a fundamental human need, regardless of the circumstances.
In addition to performing the task of looking for Madeleine for her own and her parents' benefit, SY also have a public duty to carry out in seeking and apprehending the perpetrator (s) of this crime, who may still be at large. Hence the justification for their use of such substantial public funds.