Earlier quoted context omitted.
The problem with your reasoning is that these cars were designed to not meet the emissions requirements from the factory . From day one, they were only designed to meet the emissions standards during the testing, not on the road. They were purposefully designed to cheat on the test. Your statement would be true if test performance varied from real-world performance due to environmental factors, but that's not the cas…
> Your statement would be true if test performance varied from real-world performance due to environmental factors, but that's not the case. ..or due to engine temperature, speed, gear, gas pedal position and tons of other variables WHICH IS the case. That's why emission requirements are (and must be) test-specific.
Yes, testing varies from the real world based on a number of factors. Environmental, driving style, etc. And the current tests don't care about that, which is a completely separate problem. The problem that VW got in trouble for is specifically designing their cars to cheat on the existing test.
Yes, cars behave differently if they're driven uphill vs downhill, if they're driven in the rain vs in the snow, if they're driven in the mountains or at sea level, but that doesn't matter at all. The test doesn't care, the law doesn't care. They're willing to accept that difference, as long as the car doesn't actively circumvent the purpose of the test. Which VW did.
You can argue that the test is invalid, and I agree. But that doesn't matter. The test is the test and VW cheated it. They built their cars specifically to have a completely different performance in the test vs in the real world with the specific intent to cheat the test.