It's still a lot of time with one game! you played other games during that decade too, I hope.
Plenty, especially RPGs and adventure games, and I've also always owned consoles. When people ask me what my favorite game of all-time is I often say it's a tie between Quakeworld and Planescape: Torment.
Quake 1 was unique in that it came around at a time when online multiplayer gaming was just getting started and it coincided with IRC coming to popularity (that's when Quakenet arose). Quake in many ways kickstarted the whole online multiplayer phenomenon, at least for shooters. So it had a skilled and very active core community surrounding it, as if you were into competitive shooters in those early couple years, you were playing Quake.
Counterstrike, Tribes, and UT made a splash later on, but I never bothered to go on to those since I felt (correctly
) that Quake was by far the superior game.
Nothing else I've ever played comes close to the amount of time I played Quake, and nothing else ever could. I don't have as much time to focus on multiplayer games these days (nor do I find any of them in the shooter genre nearly as well-designed), and there's no way in general I could spend even a notable fraction of that time with a single-player game.