You also don't want to destroy any physical evidence while looking for your electronic evidence, so they aren't simply going to bring in a trawler till they have sent ROV's down to photograph the wreck because even the way it is positioned under 1000 feet of water might tell you something.
Furthermore, if the wreck is more or less intact (I doubt it) lifting 100,000 lbs of Aluminum is not an easy task, even if it is broken into large sections, getting the equiptment on site that can lift that much weight will take some time...
Patience. There is actually no rush to do this. The recorders are water tight. If they leaked (extremely unlikely) they are already ruined, if they haven't leaked they won't.
Often the desire to recover bodies quickly for the families interferes with the evidence for the crash investigation because the wreckage gets disturbed.
Cheers
Wino