I don't think editorial had a choice.
War of the Supermen was originally supposed to be a major event but sales had tanked so bad in the year they built to it that I think they were ordered to wrap the story up in a month. No one was buying the story so why drag it out for several more months, as was the original plan? Keep in mind also that this was when JMS jumped ship to DC and was taking over the Superman title. Given that JMS' direction was completely counter to the scope Robinson and Rucka had built towards, the higher ups at DC were probably adamant that everything be reset.
In hindsight, the one bright spot during this entire period was the Lex Luthor Action arc that came out post-New Krypton/Blackest Night.