At the end of the YT video, the audience applause seems tepid, nobody stands, and yet the performers must be exhausted. (I think it's a great performance.) There's no singable theme, nothing really catchy, just 15 minutes of pretty intense focus required by everybody. For me, it's completely gripping - it can't be background music and I cannot do other work if it is playing. I think it is somehow alien, and so it will never be as widely celebrated as his other works.

Indeed, listening to 2/3rds of it left me in a fugue-like state.