So, I understand, at least at a basic level, the method of operation of switching converters, both buck and boost. What puzzles me, though, is why buck converters in particular aren't simpler.

Why not build a buck converter as a switch that charges a capacitor, with the switch controlled by a comparator comparing the output voltage to a reference? Wouldn't that be a lot simpler, allow you to use a more easily and cheaply available capacitor in place of the inductor, and skip the diode entirely?