Film preservation and restoration was an abstract concept if the average person even knew about it at all back then. It didn't because a rallying cry until around the time of the colorization controversy in the mid 80's. Today, it's a marketing buzzword often used when a film less than 20 years old, with excellent elements, is reissued on video for the fifth time. Disney uses it so much it's almost become meaningless.

Why didn't fans complain about the Kansas scenes in The Wizard of Oz not being in their original sepia tone in all pre 1989 video releases? They probably weren't aware it had been that way anymore than any of us were aware Star Wars had a mono mix until much later.

And the small group of hardcore film fans who knew something was changed or not right with a movie, had a very limited venue to vent their rage. An angry letter in a genre magazine wasn't going to hang in the ether or public consciousness the way angry internet postings do.

Most major Hollywood films were not available on video prior to 1980, at least not legally. The studios were deathly afraid of Beta and VHS, at least until they slowly woke up to fact it was a whole new money machine.

When studios started opening up the vaults, they often didn't know what they were slapping on the telecine. Edited for tv prints occasionally slipped under the radar. An entire run of Gone With The Wind videos had to be junked because they used a version with a prologue intended for European audiences explaining the Civil War.

If Lucas had not exerted some control over Star Wars' initial video release, (he didn't originally want it on home video at all) Fox could have just as easily used a pre-1981 print.