The one big financial incentive Disney had for doing a 3D conversion of the OT seems to be gone now since I don’t see them doing a ‘97 style re-release in theaters. The only real reason to do it at this point is simply so that it can exist in that format alongside the other movies, but the in-theater saga marathons the day before Episode IX seem to be the only time and place for it. Even then, I would think most people buying a ticket to that sort of thing would probably prefer to just watch these things in 2D.
I felt kinda sorry for the people who went to the I-VII marathons a little over three years ago who got I-VI in 2D and were then forced to watch VII in 3D. I wonder how Disney handled things for I-VIII a couple years later.