[Paul F]

Sounds easy, but it is not. Movies, TV shows, and commercials have different objectives. I don't see a practical way to control loudness on commercials vs TV shows.

It is the source material, not the network that control this.

TVs and movies use the full dynamic range of recording equipment. They like quiet and loud scenes. They generally don't compress the sound. So the overall apparent loudness is 'normal'.

Commercial produces want things always loud, so the compress the dynamic range so that all of the sound (whether quiet or loud) is compressed into the top of the volume range. This way, the apparent loudness is higher.

I don't see a way to tell sound engineers not to go above a certain volume. If you did, then all that would happen is the dynamic range available to the movies and tv shows would be reduced (making tvs and movies sound crappy) and the commercial producers would still compress the sound to the top 20% of the loudness they are allowed. Then you would turn your tv up to hear the tv show and the commercials would still sound loud. Don't legislate it. Leave it alone.