So a new documentary has come out about the crash, and new info has been released about the flight track, including a 22 minute holding pattern off the west coast of Indonesia at a known holding point, which moved the crash site north.
As well, political connections of the senior pilot make it seem like he may have done this as a political stunt that went very, very badly. Malaysia may also not want it found, because of the implications if it is discovered this was a massive murder/suicide by a Muslim pilot, right after a big political scandal.