Compositions section - Opera edit

In the Opera part of the Selected Works section, it says "The Forest Is Alive (Mori wa ikite iru; 森は生きている) (1991), after the novel by Samuil Marshak — this opera has been unusually successful, with two complete recordings and regular revivals" what is meant by "unusually"? Were there expectations that the opera would fail, or was Hikaru Hayashi's other operas failures? Did it just go above expectations, of which what were these expectations based on? Thanks - RandomEditorAAA