I agree that the 180 seems weird. She was so fired up about switching to running and the marathon and so sure she really had a shot at being a gold medal level of talent. But then when it became clear that wasnt true, why just quit?
Why not instead just say, hey, ok, I'm not going to get a medal in the marathon, but I ran pretty darned fast in the 5000m very soon after my switch to running, maybe I should pursue that.
If her real goal was to show she was such a b@d@ss that she could make the transition from gold medal triathlete to gold medal runner, why give up when her initial target event failed? Take the positive signs in a different event and give that a shot for another year.
Or if you think you have no shot at all and would prefer to just hang it up as an athlete or to go back to triathlon, announce that. No shame in being an Olympic gold medalist in "only" one event.
But to just go dark is strange.