"...how quiet all the other car makers are..."
All the other (small diesel engine) car makers make cars with urea fluid tanks for the SCR system, or something similarly explicit, obvious, and complex
VW omitted this technology. They "didn't need it."
That doesn't mean that other makers' control systems don't modulate the urea dosing to account for conditions, but they don't cheat they way VW did.
Look up the wonderful CCC tech video searching:
C3TV - The exhaust emissions scandal („Dieselgate“)
...if you'd like to see how brazen the cheat code actually was. The code reportedly actually contained the official test Time-Distance Limits chart to compare with.
Jaw dropping video. Well worth watching if you have an hour.
Here's the punchline if you're short of time.
https://youtu.be/xZSU1FPDiao?t=58m
edit: Actually this might be another issue... VWs with AdBlue, still cheating?
Biting the hand that feeds IT
