Let me put it to you like this. We all know that for everything Lucas is, he's a perfectionist - right? Quality to Lucas comes well before any other sensibilities. However he's also artistic which is why he's a filmmaker - though he often tries to do "too much" himself and in my opinion could benefit from the input of others. With this in mind, Lucas shot both ep 2 and ep 3 in HD. That's in 1080p. Now, there are many obvious advantages to digital such as being able to see what you've shot right away, being able to edit scenes earlier, you don't have the problem of being on your last reel of film, etc - and it's cheaper then traditional filming (though as it was "cutting edge technology" this may not have been a draw card at the time). And the quality is amazing, as far as digital is concerned. Even at "laserdisc resolution" (roughly equal to non-anamorphic DVD) you can show a movie theatrically.

Now obviously shooting in HD, Lucas believed he was capturing a clearer sharper image then if he had to transfer from traditional film. With this in mind, we're comparing to technology as of 2000ish. Now some people would agree that 35MM film today holds more detail then HD (though if this is actually the case then the difference is probably tiny anyway), and it's often not as sharp as you can focus on digital. Ep 2 and 3 are also much more clear with more picture information then you will find in the O-OT. When you saw Star Wars in cinemas in 1977, there's every chance the projector projected an image no-greater then DVD anyway. In fact, I'm sure that this time last decade (ie ~1996) that most cinemas I went to showed images no greater then DVD is now.

I'm certain that any 35MM print will not have as much picture information as 720p, let alone 1080p. Although there's a clear difference in quality with the 2004 DVD's to the 1993 LD's - most of that was achieved through digital filtering and image processing. If they transferred it again, and only removed large, visible, obvious deformities - it wouldn't be that different to the 1993 master, even if it was scanned at 720p or 1080p.