They could mean that wafer-starts-per-day were back up to their normal levels within 2.5 days, but the pipeline bubbles that result from destroyed wafers anywhe

They could mean that wafer-starts-per-day were back up to their normal levels within 2.5 days, but the pipeline bubbles that result from destroyed wafers anywhere in the process almost certainly won't be filled for another month. It's easy to believe that the numbers cited in the article are fudged slightly -- fabs tend to be tight-lipped -- but there are also several stages in the process where many wafers could get screwed up at once, e.g., most ion implant machines process wafers in big batches. From a vulnerability point of view, you're right that it's foolish to do so, but you need to balance satisfying Little's Law with the cost and space of equipment -- it'd just be too expensive most of the time to buy enough single-wafer implant machines to match the rate of other, much faster machines.