The conversion of Seikei University into an actual Otonokizaka Girls' High School cost the franchise a billion yen. Psychiatric treatment of all the seiyuu, who at the end of filming still believed they were their characters, was another half a billion. That was offset by the increased income most of the seiyuu acquired when their ability to be "in character" expanded to inhuman levels, as demonstrated by the franchise's lawyers in court.
Furthermore, several of the single seiyuu and two of the married ones developed relationships with the seiyuu that were partnered with them in "Save Our School," which made the fans go wild. Even though it was a VR animation that couldn't be properly watched on a television set, for a while it was still the most-watched show in Japan.
A nation that didn't baulk at making Kodomo no Jikan into an anime had no issues with Anju-Erena, who quickly became the darlings of the show. Their seiyuu, who were, after all, both of age out in the real world, married after the season ended. TV coverage of their wedding approached the popularity of Save Our School itself.
The birthdays of all nine members of Mu's became bank holidays in Japan. It was one of the most popular bills ever to carry in the Diet.
And Honoka saved the school.