Looking at it holistically, it seems pretty obvious that something like this would happen eventually. Look at the history. There have always been concerted eff

Looking at it holistically, it seems pretty obvious that something like this would happen eventually. Look at the history. There have always been concerted efforts to game the standards as much as possible. In Europe where the standards are laxer there have been lots of dirty tricks employed for a long time. For example, you use a special test car for the emissions testing. One that has an engine lubricated by extraordinarily expensive, specialized lubricants. One that uses over inflated, slick tires. And so on. Taking every inch possible. Transitioning from that sort of behavior of playing chicken with the standards to outright subverting them is not nearly as drastic a change in behavior as going from purely lawfully abiding by the strict letter of the standards to deciding to smash them to pieces the next day. Not to mention that the fact that automakers have been gaming the system by inches for so long and getting away with it almost certainly led to a widespread belief that automakers could get away with much, much more, as well as perhaps taking the standards bodies less seriously. Once they began down that road, they probably didn't realize how severely the actual emissions would differ from the "fooling the test" mode to normal driving mode. And as they tuned the performance of the vehicle the divergence would simply grow to the limit of the system, which turned out to be enormous (up to 40x). I highly doubt that anyone at any stage was fully aware, until perhaps very late in the process, that the divergence was so large. But by then they were committed. Many poor decisions often result from such incremental processes.