I’ve tried to understand this point for months now, but I really just have to ask: why would the rights reverting to Disney in 2020 make any difference whatsoever? They’ve released the trilogy on home video two or three times since the LFL buyout, albeit in the pre-existing 2011 edition, and they finally put the saga out on digital formats as well in that period. Why wouldn’t they wait until 2020 for those, too, if it was just a matter of making the most money off of them? And even when 2020 rolls around, they’ll never have the rights to the original 1977 Star Wars, so it’s not an issue of them not being allowed to restore the OOT either.
What moviefreakedmind said regarding the 2011 discs.
As for releasing the digital version in 2015 instead of waiting, that was because Fox never owned those particular rights to the other five movies to begin with. George held on to them, which means they immediately became Disney’s when the buyout happened (you can’t buy ANH on Disney’s digital download service, but you can on itunes, amazon, google, etc). Same thing applies to the tv broadcast rights.