I think the explanation as to why diesel engines create more nitrogen oxides and how the EGR works was simple and on point, but the conclusion not so much. I drive a diesel myself, but it is a 2006 model, it doesn't have adblue injection, my exhaust system only has a catalytic converter and a particle filter (and an EGR, of course). Even though it is an old model, like most cars since then it has more than enough sensors to do what VW did: individual wheel speeds for the ABS, steering wheel angle for the ESC, multiple sunshine sensors, front and rear suspension angles for the headlight height control, multiple temperature and pressures sensors on both the intake and exhaust, multiple flow rate sensors, mass air flow sensors, multiple sensors in the cooling system etc.
That's why I find the article a bit thin on new information, I'm certain the embedded engineers at Bosch/Delphi/Siemens/etc. could have done that with far less information that a more modern car has.
Did they all knew about it? Probably. Did they made hardware efforts to cheat? I don't believe it yet, that's the point of cheating, "passing" the test without having to add new hardware, there is plenty of data that can tell you if the car is really moving or in a test chamber.