Answer:
Conlon Nancarrow started writing his player piano studies in the mid-20th century at a time when self-playing instruments were being replaced by cheaper forms of musical production, such as recordings and radio broadcasts. One of the main reasons he turned to player pianos was because he found that the traditional instruments and ensembles of his time were unable to realize his complex rhythmic and harmonic ideas.
Nancarrow was particularly interested in polyrhythms, which involve combining multiple independent rhythms in a single composition. Player pianos, which can be programmed to play different rhythms in each hand, allowed Nancarrow to explore these complex rhythmic structures in a way that would have been impossible with live performers. He also found that the precision and accuracy of the player piano allowed him to create musical textures and patterns that would be difficult or impossible for human performers to achieve.
In essence, Nancarrow turned to player pianos as a means of exploring musical possibilities that were not possible with traditional instruments or ensembles. While his music was not widely recognized during his lifetime, his innovative use of technology has since inspired generations of composers and musicians.