Given neither Jerry Ordway nor Walt Simonson were closely associated with Superman in the late 90s, the weight of their input while valuable doesn't fully account for everything. The theory that there was an early 90s conspiracy might be wrong, but what I remember from discussions on message boards is that the Sand Superman was held out as a possible way of resolving the marriage issue later on. Whether the editors in the late 90s and early 00s actually entertained this solution, I don't know. But given that it was often discussed among fans, the editors had to be aware the theory was out there as one option for resolving the marriage plot.
Ordway returned to the Superman books to help Karl Kessel around the time that Mike Carlin was promoted.
He's credited with the script on this story that was a part of the Dominus arc:
http://superman.nu/tales3/typical/?page=3