Some people are born with talent. Some can acquire it. Others can take all the lessons in the world, and still not grasp that elusive "it". And that's the problem with Susan Strasberg's performance: she clearly understands the nuances and subtleties of acting, but cannot connect that knowledge to the empathy and passion an actor must have to be believable in their role.
When at the party, Eva Lovelace recites the balcony scene from "Romeo & Juliet", and the guests become transfixed, I was never sure if they were staring in awe or horror. Strasberg pauses and reflects on her words perfectly -- at these moments, one could believe she's Juliet watching and waiting for her lover's answers. But when she recites the words -- and a recitation is all it is -- the fire, the passion of Juliet for Romeo is non-existent. She could just as easily have been telling the doorman to call her a cab.
The most interesting aspect of the film was in watching the various methods of acting being presented. Herbert Marshall (who started in silents and early talkies), Henry Fonda (who started in film in the 1930s) and Christopher Plummer (one of the new method actors) are all believable in their roles and mesh seamlessly together. Then there's Strasberg, who is incapable of presenting even a fraction of the range of any of her co-stars. (Frankly, I didn't make the connection between her and her father, and wondered who she knew to have secured the role.) The film is interesting as a curio piece, and Lumet's brilliance in portraying New York's scenery. But as a moving story about the theatre, it can't touch "All About Eve".