OK City knew Harden wanted a max deal and they wouldn't pay that. A mid-season trade would have shaken up the team and they might not have gotten as much since it would have been harder for teams to negotiate a contract and they wouldn't give up as much for what might be a half season. Also, they'd get even more shit than they had before the season because they'd be breaking up a team mid-run.

Atlanta would have gotten more for Josh Smith had they dealt for him during the season or on draft night. Ditto for Utah with Milsap and Jefferson. Bynum and Howard won't command as much now.

In terms of return on asset and PR, trading Harden before the season was the only option.