Much of the time for a car like this it's more about changing the tone and maybe squeezing a bit more performance out of the car. But along with that there's usually a volume increase. It's a much smaller subset of car owners who change an exhaust just to have an obnoxiously loud one.
For sure, but nobody seeking that buys a Borla ATAK, which has achieved memetic status in car communities for its absurd volume at the expense of everything else.
It already is illegal in some places, but there's a lot of legal antisocial behavior that we let go but that doesn't get talked about as much - like watching videos in public transport on the loudspeaker, or advertising in general.