They offered Shia LaBeouf big money before to do more big budget films so it seems like he's less interested in the sort of money a studio is offering and more interested in what sort of roles they are offering. I just don't see him ever returning to Transformers when he seems more interested in the mid to low budget film roles. Honestly I think they should have been done with his character after the first movie. The whole boy and his car, the whole high school loser gets wrapped up in huge events worked really well. Second movie it was harder to justify the character's return. By the third film the only reason for the character to be there is because Paramount made Shia LeBeouf sign a three movie deal. While his character is important for the first movie you could have completely replaced his character in the third film and the story wouldn't have lost anything. The only thing they could have done in the third film is kill off the character for a powerful emotional moment but the production team wasn't brave enough to go for the emotional gut punch.