This isn't really easy, add Brian Sipe (Browns) and Steve Grogan (Patriots) to the list. Most teams don't keep their QBs forever unless they are successful. Also even elite QBs play a few years past their prime after the team that drafted them lets them go.
Lots in the old days when teams were "clubs" and they played for the fun. Today its all about the money. An elite past his prime can still draw in a few million. Remember back in the day those players had other jobs to help pay the bills and put food on the table.
This site is neither endorsed, nor sponsored by, nor affiliated with San Francisco 49ers or NFL Properties LLC. 49ers is a registered trademark of the San Francisco 49ers LLC. All teams and players mentioned are registered trademarks of the NFL and its respective teams. The use of any team names, words, trademarks, logos or photos have been used for descriptive purposes only. The content and information from other sites is the property of their respective owners. Player and team photos used with permission from USA TODAY Sports Images.