Why was the "Anime no Chikara" project interrupted?
One thing that Koichiro Natsume said was that it was a one year project. It's difficult to tell from what he said if it was planned to be one year from the start or if it ended up being one year, but if it was planned to be one year, then it wasn't aborted but instead just ended.

One thing that he said was that there were supposed to be four projects. Only three were released, which may have been the failure that he was talking about.

In regards to episode 7, they actually played a replacement episode (episode 7.5) the same day that episode 7 would be released, so they actually did have an episode that day. From reading about it, it doesn't seem as though they were forced to stream it online but chose to instead, but it is difficult to tell.

It is difficult to tell exactly how voluntary ending the program was, but Koichiro Natsume at least implies in his interview that it was intended or at least ended up more as a learning tool than anything else.