If I remember correctly, at one time Jackson wanted to make a “bridge” film that would cover the 60 years between events in “The Hobbit” and the LOTR trilogy.
This would include material from the timeline Tolkien added to the appendix of ROTK, i.e.,when Theoden and Denethor were young, and a mysterious young man named Thorongil appears in Gondor and Rohan..
I don’t know if any of this material will appear in the 3rd “Hobbit” film, but apparently plans for a “bridge” film were scrapped some time back..but then, you never know..would not surprise me if one gets made eventually.
Creative bookkeeping notwithstanding, so much money has been made on the other films, it would seem someone will want to keep the money flowing, and will make the “bridge” film..we shall see, I guess!!
Early on he was talking about all kinds of stuff like that. By the time ROTK finished though he declared himself done, didn’t want to do anymore Tolkien, had Hobbiton torn apart, clapped his hands over the table and walked away. It’s even in the extras on the extended ROTK, he talks quite a bit about how very done he is with it.
The studios will want to, but they’ve already shown they think PJ is the magic touch. It’s why they wouldn’t fund Hobbit until he agreed to at least produce. Maybe after all the bad reviews they’ll decide it’s the material not him and negotiate with the family. And, of course, eventually there’ll be a whole new batch. It’s Hollywood, they’ve been doing remakes for over 100 years.