Conduit isn't very common in US residential construction. Electricians will generally cut a hole in the drywall, drill a hole in the floor plate and tack the cabling to the framing.
Even if you aren’t using conduit you cannot use the same pathways for line-voltage and low-voltage wiring. You need to drill separate holes thru the studs to run NM in one and Cat6 in the other. You also need a divider in a multi-gang box if it contains line-voltage and low-voltage wiring.
Americans love building single-storey detached houses on big lots. And when they build an upper floor, they love complex roof systems where almost every upper floor window has a first floor roof or porch below it.
This means problems like fires spreading to adjacent buildings and fires trapping people where they can't escape are much reduced; you'd never see a repeat of the great fire of London in an American suburb because there's practically a fire break between every single home.
This is made affordable by America's vast tracts of land and high rates of car ownership.
I think that is very location dependent. Here in the Midwest, Romex still isn’t a thing and most residential construction still requires (effectively or otherwise) 1/2” electrical conduits for all high voltage wiring. Older construction might be the horrible BX/AC instead.
You said Midwest, but are you sure you don't just mean Chicago? Chicagoland is the single place I've heard about residential work requiring conduit.
I had a house with mostly Armored Cable and came to appreciate it. Especially after I opened up a floor and found an exposed conductor on some Non-Metallic that had been chewed by a squirrel.
NM wiring is extremely common in every state (except for Illinois) and NM is allowed without restrictions in multi-family stick-built housing up to four stories. You must live in Chicago or some other restrictive AHJ.
There are still existing functional knob and tube wiring systems that are 100 years old
I still have some knob and tube wiring in my home (which is 96 years old). I've ripped out most of it over the years, but it is amazing how reliable it actually is.
Were you able to do that without digging into the walls? My house had a bathroom and the kitchen upgraded by the previous owner and we did the basement but most of the house remains on knob-and-tube.
I've gradually added GFCI outlets to each circuit. They're not grounded, unfortunately, but they do trip if something were to go wrong. And it allows us to plug in 3-prong plugs without using those horrible 2-to-3 adapters.
We had to change home insurance companies because Amica blacklisted us the instant they heard there was knob-and-tube wiring. A few other companies have the same approach. But it's not like homes are spontaneously combusting everywhere because of it.
Source: US National Electrical Code