There’s also a tendency for companies to be super proud of what they’ve done so they neglect methods like A/B testing and instead just bet the farm on their great new design. After all, it cost a lot of money and looks cool to the decision-makers so what could go wrong? Um, maybe before you throw out all of your packaging everywhere and double-down, you could tone it down a little and try it out in a few small markets first? Then watch and see if sales are going up or down? Then think about going further?
And at this point there is also a tendency to ignore history. This is far from the first big failed redesign; what is going on that no one is looking at past failures (plenty of which have had high costs to other brands too), and imagining that there might be a downside?