The NVFR rating is the only rating I can think of that does not require a renewal. to meet the requirement to demonstrate instrument proficiency and a take off without visual reference would, in my view, preclude the training and issue for NVFR in major cultural lighting areas unless a complete IF hood is also used.
Until we address the lack of instrument proficiency, and the need for regular reviews of the proficiency, we will continue to suffer these accidents, rotary and fixed wing.
But at least lets adopt NVG yesterday. oh...that broken record again!