Why did modified Cyrillic alphabets differ among Soviet Turkic languages?

Modified Cyrillic alphabets differed among Soviet Turkic languages primarily because the new regional literary languages were established based on local dialects without coordination between the various projects.1

During the 1920s and 1930s, as these languages were formalized, there was a lack of common-language planning. Consequently, the graphic representations of the Cyrillic script varied considerably across the different languages. This lack of standardization, combined with the fact that these languages continued to develop independently, resulted in a wide variety of script adaptations.1