As others have said, the assumption that price reflects the quality of architecture, at public courses as well as private ones, is fundamentally flawed. Among other things, people are interested in prestige, conditioning, service, amenities and natural beauty. Many golfers (probably the majority) wouldn't care that much for Wild Horse because of its lack of trees.
BTW, I'm playing Wild Horse, for the first time, this weekend and I'm thankful the fee is under $50.