"Why should those residents get preferential rent treatment?"
Their rents are not being subsidised. The owner is presumably running the site at what he regards as a reasonable profit.
Housing land is only worth whatever someone will pay for that location because of its transport or social advantages. In turn what people can afford to pay will depend on what they earn, or have inherited, or get as employment perks.
The park was presumably established when the factors that set the price were not in big demand. The new people moving into the area are prepared to outbid each other to live in that location. The inflated prices they are prepared to pay have nothing to do with the established rents in the park.
Biting the hand that feeds IT
