I'm sure we'll get another image format based on the I-frame compression from a video codec but I agree that BPG is unlikely. More likely is we get something from AV1, which should be patent unencumbered and hopefully perform better.
It wont perform better as we already know that. Given how Internet, and now smartphone is video and image driven, i really wish there is an breakthrough in Video and Image technology. Something that compress the best of Jpeg in 1/10th of its size, but would require either dedicated HW or high end CPU to decode.
I really wish .bpg takes off. But with all the patents issues It seems nothing much is happening.