Sentence:  Separately and then together, we forged these theaters, these instrumentalities, these constellations of activities, these collective outposts, these—God forgive me!—institutions in order to preserve and re-create, in new forms, the art of theater then <WSD>fusting</WSD> in us unused. 
Meaning of the word marked with <WSD> tags:  To turn mouldy, to decay.