Back then games had to be gold to be sent to the CD/Disk manufacturer, then you had to receive the copies and send them to be packed or directly to the distributors if they handled the finale packaging.
This meant that a golden sample could circulate for as much as 6 months (and even longer) before the game would go on sale.
Also as all support was pretty much phone support which also included some basic gameplay support you would have support staff often at 3rd party call centers who would require access to the game before it goes on sale (for large games at least, small companies tended to have support in house).
Today with digital distribution even if it's for patches only you don't care about the game going gold the DVD could contain a build that is utterly irrelevant pretty much every new install from disk requires a day 1 patch that can be often as large as downloading the whole from scratch (pretty much every console owner knows this, PC games also get a day one patch but digital distribution is a given for the PC market these days).
So zero-day for games at least isn't that important anymore, also DRM is harder to crack these games some games take months to crack, some don't get cracked at all, some rely on a weaken DRM version to be released (e.g. STEAM) down the line that can be cracked more easily.
For DVDs/BR today this also often happens you have full BR rips often weeks before the official release date, sometimes months just because they are already ready just waiting on the right time to go on sale or for some online distribution exclusivity deal to end.