Lane was not iffy about taking the role until Betrayed was written. Betrayed was, in fact, a replacement song written to give the show an 11th hr number...like Rose's Turn...because Lane felt that the original song was too meager and sad. He had long ago accepted the role when he actually got this number. And he would have NO say in what Universal left in or took out. He isn't Tom Cruise.
As for the movie working without King of Broadway, the preview reports seem very positive without it but if you think about what musical numbers are SUPPOSED to do in theater...they are supposed to explain something or someone. The song 'King of Broadway' is purposely positioned at the point where the audience has left the theater in disgust and it is meant to be the exposition for Max...to explain who he is and how he has fallen from the heights to the depths. By taking it out...you see the people leave the theater, you see Max standing there and have no idea who he is and then you cut to the office and you have to figure out who Leo AND Max are all at the same time. It doesn't fit the musical convention very well...but it was cut merely for length...so we all have to live with it. Movie studios after all know more than any one else including people who produce musicals every day. Oh well...it is what it is. I am happy to hear that audiences seem to like it anyway, but I still think the movie would have gotten off to a better and faster start with the song left right where it was. But movies rarely make it to the screen unchanged. Ask any author who has had their book purchased for a screenplay. It is often unrecognizable by the time it makes it to the screen.
"Life is a lesson in humility"