According to Pro Football Reference, there are only 27 quarterbacks or players who had primarily played quarterback before in NFL history who would go on to reach at least a 17th season. 12 of those players would play their 17th season during this century, beginning with Warren Moon in 2000.
Of those 12, only four spent more than 10 of those seasons with the same organization. Even Drew Brees has ‘only’ been with the New Orleans Saints for 14 years, having spent his first five seasons with the San Diego Chargers.