Not really- the prequels were released by themselves as they came out, and when the OT hit DVD for the first time, ROTS wasn't out on DVD yet, so they couldn't do it then. By that point, most people already had the movies on DVD, minus ROTS. Later on they did repackage the OT for the non-SE versions, though they claimed they were "bonus features" and the rerelease was just for the 30th anniversary of SW "(thus rereleasing the OT and not the PT- though I think a PT boxset was made by this point). And by time that was all done, there wasn't much of a market- I mean, SW fans and the general public already have copies of the trilogies/movies they want on DVD- how many people will really rebuy them 2 years later? Even the most recent VHS rerelease waited 5 years between releases (1997-2002). At this point, they're probably just waiting to do a Blu-Ray release of all 6 movies, since thats something "new" to sell.