Yeah, in the audio production world, it’s commonly referred to as a “compander”. A compressor for the loud parts, and an expander for the quiet parts. Commonly used in speaker phones for being able to pick up a large range of volumes, meeting rooms for remote meetings, plug-and-play ballroom mic systems, overhead announcement systems, etc… Basically anything that you want to set up once and then never worry about tuning. They can be a pain to properly dial in at first, but can be extremely useful.

Indeed this is an overly solved problem. Personally I prefer ReplayGain for music and some video-audio productions while compression is great for making voices clearer. Thinking about adverts, compression would likely be the winner for making it less jarring decibel wise.