A blast from sixteen years ago: Aaron Swartz writing about how OCLC, which was started to help libraries, now controls and terrorizes them.
https://web.archive.org/web/20081218092812/http://www.aaronsw.com/weblog/oclcscam
Stealing Your Library: The OCLC Powergrab (Aaron Swartz's Raw Thought)

@mike Just before the current century started it seems the first step was taken towards the first Open Source library system: https://koha-community.org/about/history/
History – Official Website of Koha Library Software

@OpenSciTwente I'm a big fan of Koha, and one big chunk of it is software created by my employer (the Zebra Z39.50 server). Now we're mostly working on FOLIO, another major open source library system, which in use at places like U. Chicago, Stanford, Cornell and (soon) the Library of Congress.