gov still has to compensate sinkies for the "gains" made from a $36.9k flat over 36.9 years ago to today's gov's valuation of say $369k (even though the market rate may be $696k for that same flat). gov's valuation of market rate is typically well below the actual market rate. nonetheless, that's still 10 times more over 36.9 years. but at the end of the day gov recoups the cost plus earns some surplus as new flat sells for $696k, may be with a 69% margin after factoring in cost of land, labor, material. cost of land is lost opportunity cost to gov as land can be auctioned off to private bidders for much higher prices. heads they win tails sinkies lose.