Some elements of Birdman seem custom-fit to the actor Michael Keaton:
- He plays Riggan Thomas, an actor who is about 25 years removed from a blockbuster role as a superhero, just like Michael Keaton is about 25 years removed from his role as Batman
- "Riggan Thomas" has same syllable count and similar intonation as "Michael Keaton"
- The name "Batman" is obviously similar to "Birdman," the outfits look nearly identical, and the voice of Birdman sounds similar to the voice of Keaton's Batman
- Keaton turned down a third Batman movie, like Riggan turned down a fourth Birdman movie
However, other elements don't really fit:
- Riggan seems to be defined by his Birdman role in the way Christopher Reeve was defined by Superman or Roger Moore by James Bond -- but Michael Keaton was never really defined by the Batman role: he's just as popular for roles like Beetlejuice and Mr. Mom
- Batman 3 was not a commercial success, and Batman 4 was a disaster, so Keaton's exit after the second sequel seems like it was a smart career move, not something he would regret like Riggan regrets negging Birdman 3
- Keaton has never tried to re-invent himself along the lines of writing, directing and starring in his own Broadway play, like Riggan does
With all this in mind, was "Birdman" and/or its "Riggan Thomas" character written specifically for Michael Keaton?