If I remember correctly, the author stopped this series in 2011 right after the earthquake in Fukushima.
I remember reading a statement from the author years ago about how he was not going to continue work on this series because of the massive tragedy that struck Japan. Said something along the lines of "I don't have it in me to continue to write about a disaster when one just happened" or something like that. I can't find the source because it was so long ago.
Now this is just speculation but Ch 30, which was put out 2 years later, was most likely already written and probably partially layed out already when he decided to drop it. I say this because he did write other stuff after this series, so it really seems like just a matter of not having it in him to continue this series.
And although I'd love to read more of it, I feel it'd be best if others respect the authors feelings and didn't continue or reboot it. I mean, the other people who worked on it already shot the idea down as politely as they could.