DTG once mentioned on a stream that the cab on the 166 is extremely silent during the drive so I guess they have modelled it as close to the real thing as they could. But I agree, it is perhaps a bit too silent and I tend to turn the volume up when driving the 166 because I like to hear the engine. Maybe they can remove a bit of the virtual cab insulation?
I think the whole idea of driving a train is the actual noise, the sound of the engine,the changing of the pitch when it goes through the gearsand the growl of the engine, to sit in a silent cab we may aswel be flying a glider.