not USanian but afaik cars got so big over there because trucks (being work vehicles) have less (environmental, safety, …) regulations than cars, that’s why SUVs got so popular, manufacturers pushed them onto public. as long as the base for the vehicle is that of a truck they are legally exempt from many limits.
source: probably “Not Just Bikes” on y*utube idk
EDIT: just read about the chicken tax, interesting…
that’s true, but from what i’ve seen these gigantic cars really don’t offer that much more space; if space/capacity was really a concern family buses/vans whatever would be much more popular. where i live most people i see on SUVs are alone on their car, bigger families just get a Citroen Berlingo <3
but yeah people do like big cars