True, but mast bumping rarely leaves the blades, head, mast, and transmission intact. Something happened that catastrophically ripped the entire drive train out of the airframe. Assuming that they recover all the components, I’m fairly confident they will be able to determine the proximal cause.
As a chopper builder and pilot, I am acutely aware of all the fiddley-bits in the drive and controls on my craft, not a single one of which is non-critical.