Not sure why you blame USSR in this topic, as far as I know, it supported regional languages and printed many books, newspapers and magazines in the languages of its republics. I bet that books at that period were much cheaper than they're now.
The big boom in minority-language publishing came in the 1920s and early 1930s, when there were major drives to improve minority-language literacy and translate as a rule higher-education teaching materials into local languages. However, starting from Stalin, minority-language publishing was reduced to little more than a token effort, mostly socialist-realist poetry or fiction and newspapers of exceedingly local concern. Furthermore, the print runs for minority-language books were minuscule, even for very large minorities like the Tatars. It wasn't until glasnost that minority-language publishing took off again.