It all boils down to how the Byrne reboot was handled too. When Crisis on Infinite Earths was written there were NO plans to "reboot" Superman, which is abundantly clear if you read COIE#12 and the titles that came out a bit after that but before the reboot (for example History of the DC Universe referred to the Earth-1 Superman, as did the pre-Crisis Luthor in Moore's Swamp Thing). Even when it WAS decided the editorial direction seemed to be very light. Byrne was given more or less free hands because of his superstar status, and how that affected other titles he didn't give a damn about.
Of course, Byrne isn't really a fan of anything but the big-name creators like Kirby or Ditko, so it's no wonder his revision was very rough on the works of others.