Cabin noise, especially turboprop noise, comes from a very wide band and source. You have the prop sounds, engine sounds, and extensive vibration sounds through the fuselage which comes from the walls, wing carry through. Airflow sounds as well. From all directions. And it comes from the other side. ANR can only really work well where the microphone is located very very close to the speaker, and the sound is mainly coming from one direction. You are essentially trying to double the sound energy in the volume involved to try and cancel out the initial sound energy. I can't see how even in a car cabin it can possibly work, and can make the problem worse in certain areas. There is another problem. If you do manage to neutralise the sound energy, how can your microphone pick up the original source? Over a larger volume, the mike picks up the sound, it's processed and the speaker pumps out 'deadening' sound. So the mike then picks up low noise- reduces the demand for deadening sound, so initial noise comes back- mike picks up loud noise again......in short, throbbing noises? Why don't you have a 'feedback' loop like when people are speaking into a mike at fetes when they get drowned out by a whistle?
It's been hard enough to get airlines to pay for ANR headsets (I bought my own). For the limited efficiency and great cost of installed systems, I can see why nobody really bothered buying such area systems. I can't see it getting much beyond ANR headsets.