I played Torrey South for $128 this year, and two rounds at the Ocean course for around $600 (including caddie). Torrey is a muni, while Ocean Course is a public course owned by a private resort company. This explains some of the price difference.
Torrey was incredible, but it was not as nice as Kiawah. Torrey was completely booked with foursomes. I was hit on from 110 yards out, and I had a group of guys jamming techno from the adjacent teebox.
Ocean Course was barely booked (not fantastic weather), with only twosomes, caddies required in the morning ("watchdog effect"), and Ocean Course was in perfect condition in every area on every hole. The pro shop was much more expensive too.
I think this explains why some public courses cost as much as they do, or why some don't.