Now that we know the rough area of the aircraft, technological advances in mini-submarines etc. should allow us to find MH370 quickly. The batteries are also designed to last a long time, and the black box stores the information in such a way that it will last a long time before being destroyed.
Although there was plenty of hope early in the search that the pingers would lead searchers to the wreckage, the batteries were only good for 30 days, which have passed. At this point, even with the narrowed search area, any discoveries will be the result of seabed exploration and a good bit of luck.
This whole situation with what happened with this plane is a mystery. The fact that it actually took so long to actually figure out what happened tells me that it will probably take even longer to find out where the black box is located. The search had been going on for quite some time and there is no end in sight.
The area to search for Malaysia Airlines Flight 370 has been narrowed down, but the batteries can not last very much longer in order for the black box to put out even a weak signal. Underwater signals detected in the search for the missing Malaysia Airlines jet have stopped in the last few days. Without pings sent from the plane’s black box, it will be almost impossible to locate it.