Converting to anamorphic does involve upscaling the picture slightly. This is almost the last thing any studio or mastering facility wants to do. The only benefit I can really see is one of convenience - of not having to adjust your 16:9 TV/projector to make the image fill the screen horizontally. I converted my set to anamorphic only for this reason. Remember that the laserdisc masters were originally only ever intended to be seen on a standard definition 4:3 screen, and when viewed this way they look barely distinguishable in terms of clarity from the anamorphic SE DVD's.
I disagree. Having gone through SW:ANH GOUT frame-by-brame from start to finish I can clearly see that the port from the D1 tape (or D2 whatever it was) isn't perfect anyway: there are IVTC errors in there (though only a handful here and there). I've never encountered a NTSC telecine DVD that I couldn't IVTC without errors in avisynth; for instance Chriterion's Robocop comes to mind; that's a straight port off their LD tape complete with DVNR smeering and all the rest of it just like the GOUT; except they didn't even IVTC it before releasing it on DVD (mind you that was in the early years of DVD).
They had to convert it between PAL and NTSC anyway; PAL is an upsize, NTSC is a downsize depending on which way they went (and they went both ways apparantly going from NTSC to PAL for SW and ESB and PAL to NTSC for ROTJ). Not doing an anamorphic job is really slack. Plus, considering the clarity and detail in the 04 DVDs it is unacceptable that they didn't do the same for the GOUT. It's not the only DVD like this, The Exorcist comes to mind: the theatrical version was not updated when the special edition version (which I don't like as much) was released, and I don't understand why that is either. If there's any interest I might be able to do a similar thing for this movie using avisynth as I've been doing for SW (and I have both the NTSC and PAL versions of the Exorcist, reason being I bought the PAL version first and I wanted to see the Exorcist III so I boubht the NTSC boxset off Amazon and a great price that has all the movies in it!)
The DVNR is on the master tape, yes we know that. That means they needed to scan the altered scenes from the negative again. Blade Runner, Close Encounters and E.T. all have their theatrical versions intact in modern transfers on the DVD alongside the altered later versions (though it took forever for close encounters to be released on DVD too).
LD's were not designed for display on everyday TV's, they would have offered almost no advantage over VHS if that was the case. They were for the high-end market with the very best TV's, projectors, etc.