Considering what the Gamebryo engine actually does, I'm amazed Bethesda games have so few bugs. Things like random NPCs appearing in weird places, strange interactions, misplaced landscapes, scripting conflicts that screw up quests... those type of things can't possibly be totally accounted for when you have the number of variables that exist in a sandbox game.
Don't compare it with a linear shooter, or any other kind of game. There's a limit to what you can "do" in those games, so they're easy to bugtest. The number of variables you can screw around with is much smaller. Bethesda games are ambitious, and as such the risk of random things conflicting with each other is obviously going to be higher.
I think what Howard is talking about is that they prioritize their bugs. That's what all developers do. All the bugs that the community moans about are probably the ones they try to catch. Just think of all the bugs they already dealt with.
Excuse me while I alt+tab back to FNV... having it crash every 5-6 exterior loads... but still loving it.