Especially technical documentation. No public docs or training on any of the dominant operating systems back then. All proprietary and expensive and private. My biggest thrill came when my company bought a Unix system to replace our mainframe. I could actually buy books in a bookstore to learn the operating system.

Back then the tech "became penetrable". The old impenetrable tech was at a great disadvantage when this happened. The old companies had to change their ways or die out. I don't think tech can ever become more impenetrable (artificially controlled) than it was back then.