what is the point of providing "behind a paywall" content? Especially when referring to the The early days of Linux, which is open source. Open source software

what is the point of providing "behind a paywall" content? Especially when referring to the The early days of Linux, which is open source. Open source software is code that is designed to be publicly accessible yet I cannot read about it. A paywall describes a method of restricting access to online content via a paid subscription. what about those of us who cannot afford such subscriptions