There wasn’t really an equivalent of Sci-Hub and LibGen until the last decade or so. I was a member of previous filesharing communities popular among Eastern Europeans unable to afford academic literature, but there wasn’t all that much available in pirated form, because it required time-consuming scanning or making a request to someone who might download it for you. It was only when people like Aaron Schwartz and the Sci-Hub team managed to mass-download articles from JSTOR and other paywalls, that finally academics got access to most of what they were looking for.