I'm saying you're citing a "tradition" that isn't.
It will be! *pounds fist*
I just can't see them getting rid of the Jedi. Not only would that be a huge change in the brand, it would seem like a slap in the face to Luke. Unless Luke himself decides that it's stupid to be a Jedi, then his whole quest was for nothing. Learn these things, redeem the father, re-establish the Order, get it all torn out from under you, go into exile, have your (potential) apprentice who is the only one who can carry on the mantle leave you behind?
That doesn't seem very Star Warsy. The Jedi have to be ultimately victorious, even if they have to reform. And reforming the Jedi isn't the same thing as destroying the Jedi.
Unless, like I said before, Finn ends up becoming a Jedi and refounds the Order, or there's some new character, or Leia survives and does it. Or
something. But if it turns out that Finn's not Force sensitive and Leia dies and Rey is the last one standing to increase the weight of the situation on her shoulders, I can't believe that Lucasfilm would have her abandon the Jedi and let them die once and for all.
edit: The Sith aren't as integral to the franchise as the Jedi either, they've only been in the public eye as the main villains for the last decade. Even though Vader was described as a Sith from the beginning, the concept wasn't fully fleshed out and most people didn't even know about that. In story terms they're equals but in franchise terms I don't really think "Sith" reaches the same levels as "Jedi", who have been upheld as the guardians of peace and justice since the first movie.