We all know how it works; the next movie in the series is released, and so you get a boxed set containing all the movies to date! You can understand the temptation to do that boxed set for Star Wars, too; imagine a gorgeous boxed set, with a raft of Special Features, containing Episodes I through to VII!
Unfortunately, that's not going to happen anytime soon.
When Disney acquired the rights to the Star Wars franchise, a number of things were already contracted out for a set period. The Star Wars comics, for example, were contracted out to Dark Horse until the end of 2014, when they were transitioned to Marvel (hence Marvel released their Star Wars #1 in January 2015). The distribution rights for the previous films were already contracted out to Twentieth Century Fox - and those rights don't revert to Disney until 2020.
This means you're not going to see a boxed set containing the older films and, say, Star Wars: The Force Awakens. In fact, because Star Wars: Episode VIII comes out before 2020 (it's due out on May 24th, 2017), you're not going to see that boxed set for Episode VIII either. By the time Star Wars: Episode IX comes out, in 2019, the rights will be about to revert - so 2020 could be the earliest we'll see a boxed set, but one that could potentially contain all three trilogies.
That said, I'm willing to wait. The idea of a boxed set containing three Star Wars trilogies? Yeah, if Disney choose to release that in 2020, I doubt price would be an object for this fan.
Source: The Hollywood Reporter