Not only printing stocks. But also the dyes --3 very stable dyes as opposed to 3 plus a silver record -- the mortar, optics used to create the matrices... The list can go on.
Totally different imagery, based upon the same negatives.
RAH
The process itself was not "fuzzy." The resultant prints, based upon the technology of the era, were on the soft side, and hid a multitude of sins. What you were viewing in the '70s would probably have been derived from one of the printing CRIs then in use, which were far sharper.
The rationale behind wire and physical artifact removal has nothing to do with the ability of the filmmaker to remove them in the past. The point is that there was no necessity to remove them. They could not be seen in final prints, and DPs of the time knew this with precision.
RAH
While I can't speak for WB, I can tell you that during the early period in which OCNs were being digitally scanned, that there was a "wow factor" regarding the amount of additional information being harvested from the film during the process. Details that had never been seen before in the...
Wires were not visible in 1939. Same situation in a number of Chaplin films. Also in Godfather Part II for that matter. Wires needed to be removed in two sequences.
Wires now show when OCN is scanned, especially at 4k resolution. Removal is a necessity for viewing and is not a matter of...