In theory the pricing should be there to control supply and demand and stop effectively people living in the parks for extended periods. But instead of cranking up the price, they could do more to limit the length of stay, the size of groups, the number of times in a year you can stay, time you can book ahead and so on.
I agree Bonnie Vale is too expensive, but its a great spot too. Its right on a beach, has big sites, very good grass, nearby shops, walks, good showers with plenty of free hot water, wash up area, dedicated areas for tens, vans and CT's.