Very popular shows often had fans write stories about future episodes AFTER the show is cancelled. The show Dallas had people all over the world write fan fiction for that show.

Season 12 was supposed to happen because they already planned to have Lionel move back in with his parents after his divorce so now new storylines can be created with Lionel living home again.

Fans could've written new stories starting from there like Lionel's new love interest, friends, job, etc.

You can always email Fanfiction.net and ask them to put a category devoted to The Jefferson’s.

Wow! It took over a year for an answer.