Complex sentence: He also executed a rare move by not signing a contract after arriving in Hollywood, only doing so after his first two films were a success-- "a power differential that would go on to structure the star-studio relationship for the next 40 years".
Split into simpler sentences: He also executed a rare move by not signing a contract after arriving in Hollywood, only doing so after his first two films were a success. This was described as "a power differential that would go on to structure the star-studio relationship for the next 40 years".