In the urban eastern U.S. apartment buildings usually run right up to the road, except a ~ 1-3meter sidewalk. There isn't sufficient visibility to yield safely; both directions have to come to a stop anyway to check for cross traffic.

In the western U.S. (and eastern suburbs) the 4-way stops are largely vestigial; I'd agree that most of them could go away without any loss of safety. Many of the newer neighborhoods are signed that way anyway, though - I just drove through one this morning with 2-way yields.

My driver's ed class was IIRC 36 hours of instruction and 12 hours in the car, with a professional driving teacher. It had an hour long examination putting me through as many challenging situations as possible at the end.