I build some houses along the water in the area from Rockport to Matagorda, and I think the "rock bottom" prices are just the prices getting closer to what the property is actually worth.
I think the area around PO may lack the infrastructure that they have in places like Rockport to warrant the prices they are trying to get.
But like Tupa said, people are willing to pay outrageous amounts for something on the water.
Before it opened, I drove through The Sanctuary, and it seemed like it was going to be a pretty nice place.