Erik really should have read the fine print
Did he get screwed by the Devil or what? OK, the deal was for him to become a FAMOUS composer, right? He was already gifted, as we saw from him playing before, so he wasn't asking for talent, just recognition.
Sure, says the Devil, and before you know it Erik's signing his soul away... not realizing, to his sudden horror, that he's losing his face in the bargain. Must've been in the fine print.
OK, the Devil tricked him there, but at least he has to stand behind the fame bit, right? After all, he said "The world will love you for your music..." even if Erik is hideously disfigured, he's still got that small comfort to look forward to, right?
Apparently not. Years later, he's still unknown, composing in secret, and can only get his work even acknowledged by KILLING PEOPLE. Even then, nobody except Christine really seems to appreciate it. The world is hardly loving him for his music.
Then, 100 years later, Erik is STILL trying to get his work performed. It's taken him all that time to mount what I have to assume is the FIRST staging of any of his operas, because he doesn't appear to be that well known even in the 1980s. Erik has gone all these years unloved and unknown for his music as well.
Moral of the story: if you make a deal with the Devil, always read the fine print.
The war is not meant to be won... it is meant to be continuous.