Geb is almost certainly out of the Olympic marathon, according to an article in Athletics Weekly. The Ethiopian Athletics federation has been reported as provisionally selecting the four fastest of this year, from Dubai, to represent the country. Geb himself has said on Twitter that it looks like it is over, though previously he was talking about one more effort to get a fast time. Also, Jos Hermens has suggested he stop.
The writing was clearly on the wall, but a part of me was still hoping against hope he'd make it.