The answer is : Widespread film distribution increased revenue and popularity; therefore, film companies expanded in order to produce and distribute more films.
Films are not just arts. It also about business. Basically a successful film with impressive production can expect higher return of revenue because they have established an impression to their fans and movie goers about their quality of their movies and productions. Successful films normally has parts and sequences. Since film industries are also businesses they are struggling more to develop higher quality movies with unique and impressive storylines in the future.