At this point I'm guessing it was hijacked or otherwise a victim of foul play, and then the perpetrators screwed up somehow which is why no one now wants to take credit for the affair. I bet we're going to hear conspiracy theories for years.
There is no hard evidence for it, but a suicidal pilot who wanted to make sure his insurance paid out would also explain this. Suicidal and psychopathic.
It's horrific, but it has happened twice before.
Yes. Apart from insurance, someone might care about their image, even after death, so making a deliberate mistake and causing an accident, this might not be acceptable for them.
>Would there not be an easier way for a pilot to purposefully crash that would also be covered by insurance?
Maybe, but could it be done without leaving evidence on the flight data recorder and cockpit voice recorder?
One scenario that the current limited data fits, is an attempt to hide the evidence in deep ocean, far from the search area.