Eh I actually think driving is a very cognitively difficult task. This sort of "why can't people just drive correctly" mentality is part of car propaganda. Make everyone believe the system is fine, it's just those bad people that are the problem. Then rather than changing the system you just try to punish the bad people harshly enough. Which really doesn't achieve much given that the vast majority of collisions don't involve a conscious decision to do anything nefarious.

The driving experience varies wildly depending on where in the US you're driving, I assure you: There are plenty of dangerous and very badly designed roads in America.

Never treat driving as easy, even if it feels easy (I have felt what you're describing but another word for it is just complacent). Driving very likely the most dangerous thing you do on a regular basis by a wide margin, even if it doesn't feel like it.