Sorry to single you out because nearly everyone in this thread seems to be thinking along the same lines, but do you realize that there are multiple GOTY awards? Please correct me if I'm wrong because I really don't know, but to the best of my knowledge there isn't a most prestigious GOTY award like there is an Oscar at the Academy Awards for cinema. Because of this, you can't really authoritatively say that one game is the true GOTY.
Yes TES games do quite well and often win GOTY awards, but I do know for a fact that Nintendo games, especially Zelda games, win GOTY awards as well. Three out of the last four console Zelda games (Majora's Mask is the exception, but to be fair it did win fan's choice game of the decade at Gamefaqs for 2000-2009) have won GOTY awards. If you go by aggregate reviewers (which I would argue are the most authoritative sources of determining the rankings of games), then Nintendo games win GOTY more frequently than any other developer. On Gamerankings, Nintendo games have been GOTY 5 out of the last 10 years (Metriod Prime, Wind Waker, Twilight Princess, Super Mario Galaxy, Super Mario Galaxy 2).