From what someone said earlier in the thread, sales of the 2011 discs have actually gone up since the reissue in 2015, no doubt due to the renewed interest in the franchise from the new movies.

Disney need only ask themselves, are these increased sales going to sustain themselves over the next three years or will they dwindle to the point that a remastered release of the unaltereds would be worth it, even though it will likely be the last time many fans will ever buy those movies and Disney will have nothing left to sell them post-2020.

I think the more likely scenario is Disney simply waits this out until 2020 and includes a 4k-remastered transfer of the unaltereds with the UHD release of the SE and uses it to help hype up that release. They could also release it on regular blu-ray the same day.

Disney may or may not release their own movies (TFA, RO, TLJ, etc) on UHD in the meantime. I suspect they will, if only to take advantage of that quickly growing market. It will be like how TPM and AotC were released on dvd first. Lets not forget how GL wanted to wait until after RotS to release the OT on dvd at all. This time something similar “May Actually Happen” (-Egon) regarding the OT on UHD, just for different reasons.