* Nature of his Work: Nirala's poetry is often complex, philosophical, and sometimes even politically charged. These themes might not be easily adapted into the typical song structures and melodies of Bollywood films.
* Time Period: Nirala lived from 1899 to 1961, and his most prolific writing was in the early to mid 20th century. While his work has been adapted for radio and theater, it might not have resonated with the film industry during his lifetime.
* Modernity: His style, known for its experimental nature, might not have been as widely appreciated in the context of film songs which tend to follow traditional melodies and structures.
However, there have been instances where his ideas or themes have been adapted in film music:
* Influences on Lyricists: It's possible that some film lyricists were influenced by Nirala's style and vocabulary, even if they didn't directly use his poems.
* Adaptation of Themes: The themes of love, nature, and social issues found in his poetry might have been subtly reflected in some film songs.
It's important to remember that while there might not be direct adaptations of Nirala's poems in Hindi films, his influence on the Hindi literary world, and therefore on the film industry, cannot be discounted.