LootHunter: According to some youtubers Disney tries to avoid original characters whenever possible, because Lucas still recieves royalty for them.
Breja: Ah, so that's why Obi-Wan is getting his own show and they're bringing back Palpatine and Lando for Episode IX.
The somewhat qualified rumor is that Lucas does indeed have partial ownership of the original movies and characters...
...and Disney had wanted to only re-introduce (and then kill) the original characters to initially get audiences into theaters... where they would hopefully be hooked by the new characters. Obviously, Disney made some costly miscalculations and...
(even TFA -- crossing the billion mark -- wasn't the size of a "hit" Disney had expected and borrowed against. crazy)
... that made them keep adding original characters to their movies -- even finally breaking down and Iger asking for Lucas' input. This is when we suddenly see The Mandalorian and the green-light for the Obi Wan series.
Remember, Disney had seriously thought of making "reboots" of the original trilogy -- with new actors, tweaked characters, and changing the storylines just enough for ownership -- so they could own the characters outright. Yes, they were really thinking of doing that just to push Lucas out.