I think Simpsons would probably be hard to reboot because its concept doesn't really lend itself to that type of thing. There have been what, 4-5 actual, permanent plot developments over the course of the series?
Once (if?) the series goes off the air, I expect it will become something like Mickey Mouse and Looney Tunes - even though no new material is being produced on a consistent basis, it will still be a merchandising giant.