The legacy of various famous games was lost after the Void Century. The wars that occurred pushed the world to the brink of extinction, and that most of the former technologies and records were lost.
Most of the records for all games were stored in computers and on cloud servers right before the war. And as the war wrecked and destroyed all the headquarters of many games, it wiped out most of the older games.
Cartridges, CDs, and other devices used to store the data of these games had been destroyed due to the war, and whatever survived would face the test of time.
The Void Century was a depressing and challenging time. The WGP had to find ways to keep the morale of the world but had to ensure that the entertainment of everyone would not be time-consuming or addictive as everyone needed to put in one-hundred percent of their effort.