Short answers, pulled from the story.
Gary Gygax and Dave Arneson released the first edition of Dungeons & Dragons on the 1st of January 1974. This release introduced a system where a character's fate was decided by a hidden ledger of numbers known as statistics. These statistics became the invisible architecture of the fictional world.
The game Champions introduced the point-buy method on the 1st of January 1981. This system allowed players to construct their characters with precision and fairness using a fixed budget of points. It replaced the chaotic nature of earlier random attribute rolls.
Shadowrun was released on the 1st of January 1985 and introduced a dynamic skill system. This system included complex networks of penalties for using similar skills and allowed skills to be adapted to a wide range of situations. It marked a significant departure from earlier games where skills were fixed and rigid.
The game Over the Edge released on the 1st of January 1992 and redefined the concept of traits. In this system traits were chosen by the player during character generation to allow for unprecedented customization. The game also introduced the concept of derived statistics to determine a character's ability to perform certain tasks.
The system published on the 15th of March 1983 included attributes like Strength, Dexterity, and Constitution as primary determinants of a character's existence. It also expanded to include social characteristics such as Charisma and Intelligence. These attributes could range from 1 to 100 with each point representing a significant increase in capability.