The difficulty for BEA is that, given the known facts, several perfectly viable but dissimilar scenarios describing the event and, more importantly, its cause cannot be ruled out. These range from a (simple) mechanical failure leading to upset (pitot blockage) to super turbulence/shear and the hand of God knocking the aricraft from the sky (unusual attitudes and airspeeds causing pitot disagree). Each of the viable scenarios implies different "parties at fault or blame" and each implies the application of differing safety measures and industry recommendations.
Unless BEA is in possession of significant information not placed yet in the public domain (and discussed in this exaustive forum), they need more data to reach a conclusion that will satisfy the community; best, of course, the CVR and FDR to tell them in detail what the pilots and the aircraft went through at 0210 on June 1, 2009...
France is obligated by international treaty to "solve" this mystery and can't just bail out of the search for AF447 wreckage because it's too expensive. This is not a third-world country and France would suffer a world-wide loss of face, especially for a country that prides itself in underwater exploration and technical prowess.
So the promised
early September announcement from French Secretary for Transport, Dominique Bussereau, about continuing the search is delayed. From BEA, no updates since May. Time will not sweep AF447 under the rug and out of the world's eye, so patience is required while the authorities scramble to get their ducks in a row and their financing in place. Only if the search is called off and BEA presents a slippery conclusion will the conspiracy theories begin. I, for one, can't see that happening.
GB