Yes, I suppose at some point they may want to rediscover history, but unless a legitimate story necessity for them, why worry about them at all? Are you going to introduce some force-based disease that kills off the Jedi again, or another powerful force-user, based off of the measure of midichlorians? They served their purpose in the prequel trilogy: to explain both how powerful, and possibly his conception, Anakin/Darth Vader was. There was no need for them after that: We know the Skywalkers are powerful, and that Luke and Leia are his kids. Unless you're going there's some reason to prove in the movies that Anakin might have been conceived possibly by the influence of Emperor Palpatine himself (something I suspected - why else choose Darth Plagueis's ability to conceive life in the film?) that proves important in the later films, why bother with it at all?