Not any time soon I hope. Every new release of a Zelda game is still an A+ title. Though there has been many Zelda games, the market is not yet saturated like with games such as Tony Hawk, Guitar Hero, Call of Duty, etc. where all the games are almost the same. Zelda games always have something new and exciting and the core of the game is still solid.
With that being said, there is always a way to end a series, but you can never make all the fanboys happy no matter what you do...