I mean, that sale ran for something like 11.5 days, it had to end sometime. And they stated from the start when it would run until; Steam set the timing of that, it was their holiday thing, not something specific to AI War. And now the holidays are over..
Anyway, I wouldn't worry about never seeing another AI War sale, or anything like that. We tend to do sales every couple of months, though generally of 30% and not 50%.