HONG KONG — Hong Kong is a famously efficient city. Residents pride themselves on the flawless operation of the subway system and the airport. For 21 years in a row, the Heritage Foundation has ranked Hong Kong as the world’s freest economy.

But free markets come at a cost. Easy access to capital, years of record-low interest rates and an acute shortage of supply have made Hong Kong the most expensive place in the world to buy a home. Apartment prices set an all-time high on Aug. 2, according to the brokerage Centaline, up 18 percent in a year. They have risen 158 percent since their post-crisis lows at the end of 2008.

That also makes them the priciest properties that anyone on earth can find. They are “severely unaffordable,” according to the tracking group Demographia, and in 2015 posted the most-extreme figures in the 11-year history of its global housing-affordability survey of 378 metropolitan markets. The average home price is 17 times the median income — 60 percent ahead of Vancouver, British Columbia, the second-most expensive place to save for a home.

The rarefied prices have an inverse effect on architecture and design. First-time visitors to Hong Kong are often shocked by the remarkable uniformity of this densely packed city, full of billion-dollar residential skyscraper towers that are largely interchangeable. Barring a few exceptions, the world’s most-expensive real estate consists of commoditized rectangular boxes of concrete, even at the very high end, that sell for as much as $12,000 per square foot, or $83 per square inch. So the most “luxurious” property in the world in terms of price is the most lacking in imagination.