Michael Keaton is totally right – one big flop could signal the end of a director’s career. And considering that Tim Burton had only released Pee-wee’s Big Adventure and Beetlejuice by 1989, he had yet to cement his status as a lauded director. There was also a lot of pressure for Keaton to succeed as Batman. We know now the Oscar-nominated actor can genre-hop with ease, but 1989 film critics weren’t so sure. Roles like Beetlejuice had caused Hollywood to typecast him in mostly comedic parts, and the Dark Knight is definitely not a humorous role (unless we’re talking about the Lego version of Batman in The Lego Batman Movie).
Source: Cinema Blend