Depends. The cheap houses, yeah, there's as fair bit of noise, but you can't hear everything. From downstairs, you can hear when someone walks across the room above you, but not when they're walking in other upstairs rooms. And from rooms on the same level, you can hear if someone is talking loudly in the room next door, but not enough to make out what they're saying unless they're yelling.

Well-built houses or buildings made for occupancy by multiple families usually have better sound insulation between the rooms/floors/units, so it's not always an issue.

Edit: the plus side to that is I know all the noises my house makes at night, so as a light sleeper, I know when something is wrong in the middle of the night, and I only need one decent sound system for the whole house, which is great for listening to records while doing housework.

Not really, unless the house was built incredibly cheaply with thin studs and crappy drywall.

Wood is pretty decent at blocking sound -- it the voids between the studs that's an issue. Filling them with sound deadening insulation solves that problem.

It's not as good at blocking sound as a masonry wall obviously, but it's "good enough" at a fraction of the price.

it's extremely common for americans to dismiss apartments because they simply cannot fathom the idea of housing that actually blocks noise, it's one of the primary arguments i see used against denser housing.

I want to say that stick-built homes are really not so fragile as people seem to think. There's tradeoffs, of course, and ways to build them that make them uncomfortable at best and blatantly unsafe at worst. That being said, they're pretty sturdy, fairly easy to repair and modify, and relatively quick and cheap to build.

It's a big improvement from making them from straw.

Structural use means load bearing. So no.

That was one example, you can also strap roofs to install sheet metal cladding. Is that not structural? Strap a ceiling? There’s a ceiling use for you.

I figured if I gave you a real world example you could do a little research of your own. Even googling 2x2 will get you a big box store furring strip page. You should know what furring strips are if you are in the industry.