Don't forget licensing. On the top-selling games are other games which are based on the Quake/id Tech source code: 3 Half-Life games, 2 Counter-Strike games, and American McGee's Alice. I'm sure only a small percentage of Half-Life 2 code can still be traced to its Quake roots, but it's still some impressive technology. (Alice is a little more obviously derived from Q3A.)
You forget the Call of Duty engine which is, if I'm not wrong, still made of Quake engine code... Sure, others made trully successful games with their technology. Others, like Valve, actually did the video games history since the 2000's. ID not. I'm sorry for that, but it seems to be true.
You seem to be arguing that id Software's games since around 2000 haven't been very good... but I'm not sure why, since nobody here is really disagreeing with you on that point.
The argument here is that lots of successful games are buggy, and id Software's games aren't buggy. Trying to run BioShock on my computer is a nightmare (you have to mess with compatibility settings, and even then you get no sound at all). When I played Fallout 3 it crashed about once every few hours of play time, and that was late 2012 with no add-ons -- 4 years after the game's release you'd expect patches to address things. Bethesda has a kind of reputation for releasing buggy games, it seems.
