Crankin---This happens in the close-in suburbs of DC, which are decidedly not small town in any regard! ;-) I think you've hit the nail on the head w/your assessment of it being "self-absorbed," an attribute shared by parent and 'spawn' alike. The parents or nannies, of course, congregate where the buses stop, and are more a hinderance than help in moving the kids along. What kills me most is the fact that the parents/nannies drive vehicles to pick up the kids---these folks live within blocks of where school bus stop. So their big SUVs add to the congestion.
My mom was a stay-at-home (this was the 1970s). Granted, she was sick but she was not incapacitated. Except when I was in kindergarten, she never, ever took us to or waited for us at the bus stop (this enabled my youngest brother's tendency to run for home, in tears, when the bus approached, during his first month of first grade). As a matter of fact, none of the neighborhood moms or dads felt it necessary to do bus stop duty.
You'd think, with adults there to fetch the kids, that things would move along quicker. Seems to be the opposite...