Why aren't houses more sound proofed? All it takes is loads and loads of expanding foam in the walls. Distance plus separation equals quiet. The less walls touch, the less heat and sound conduct through them.
We should build houses and apartment buildings with lots of expanding-foam-filled walls. (and floors and ceilings.) Never again will you be woken up because your neighbor, the one who loves loud stereos turned up to 11 and no taste in music, decided that 4am was a great time to drive up and down the block with his stereo maxed out. In fact, if someone in the apartment complex decides to throw a big noisy party, you'd never notice.
I know this is possible because Victorian houses are built this way, and they are famous for being very quiet. And also nice in a thermal way, if you retrofit them with air conditioning.
One other advantage is the disruption to thermal transfer. This means that when you air condition it in the summer, it stays cold, and when you heat it in the winter, it stays warm. No sense air conditioning the entire world, you know.